With all of the questions lately about detonation, and after personally breaking two piston ring lands, I was very curious as to why this phemomenon happes, as i am the type of person that has to know why things do what they do I will discuss what I have learned recently, from many web sites, and people I have talked to. Most of this is fact, although some may have their own opionions, which is excellent for discussion. Lets make this an informative post, and lets all learn what we can do to prevent detonation. I'll start off by a technical definiton of detonation.

Detonation is basically an uncontrolled, uneven burn of the air/fuel mixture. Ideally, the mixture, will be ignited by the spark plug, at the top of the mixture. It will then ignite, and burn outward in an even, controlled manner, to the end of the mixture, closest to the piston, also called the "end gas". Detonation is when the top of the mixture ignites, and then the middle or the end gas ignites suddenly. The two flame fronts collide, and cause an EXTRMELY high cylinder pressure, which makes the cyliner walls and other components go into oscillation, causeing the "knock" or "ping". Factors that can promote detonation:
Increased cylinder pressure( ie. more boost pressure)
Lean air/fuel ratios
Increased intake air temps ( reason why an IC is so important)
Advanced igniton timing
Over heating of the cooling system (insufficient cooling, esp the radiator)
Low octane fuel

-Increased cylinder pressure: This happens when we run more boost.
The more boost we run, the greater the chance for detonation to
occur. Higher compression engines will have a much greater chance
for detonation, because there greater cylinder pressure (pretty
much why most will advise going low compression and turbo)

-Lean Air/fuel ratios: One of the greastes causes of detonation. Lean
A/F caused a very rapid heating of the cylinder and cylinder
pressure, causing detonation.

-Increased intake air temps: Again, this raises the temp of the air
charge, makeing detonation more likely. Thats why an IC is so
important to use no matter what boost you run. The cooler the intak
air is, the less likely detonation is to occur

-Advanced igniton timing: This again causes very hot air temps in the
cylinder, which caused the end gas of the mixture to ignite, that
= detonation

-overheating of the cooling system: Our cooling system IMO, cannot
sufficiently handle 15+ psi of boost effectivly. The more boost you
run, the more heat generated. And the more heat, the greater the
chance of detonation. A fluidyne or better cooling radiator is a
def good choice. When the coolant is too hot, it keeps the
cylinder walls too hot, thus making a greater chance for detonation

-low octane fuel: Dont run it. When i detonated, i was running 93
octane. My A/F was a consistant .93-.94 at WOT. The higher the
octane, the slower it will burn, which is perfect to help deter
detonation. Even with 93, i detonated because of too much timing
advance.

So what can us turbo and N2o guys do to get rid of this engine killer?

From my own personall experience, any boost pressure over 8 psi, you will need to retard igniton timing. How much, well, that is still up in the air. Dyno tuning will be the best if not the only way to dial ignition retard in. Timing retard is THE best step to take, and an imperative step to take when turboed. This is esp true for stock internal turboed people, as stock cast pistons will easily crack ring lands off of them with just enough detonation. Lower the compression ratio of the engine. I have gathered that 8.5:1 is a general rule of thumb, some may digress. A higher compression engine will need more ign retard to prevent detonation. More retard= less power. Upgrade your cooling system. Get a fluidyne or similar radiator to help coolant cooling. Be sure your fans are working properly. Get a 160 degree thermostat, this will help lower the engine temps slightly. Get the drift so far? Lower intake air temps, retard timing, keep the engine from getting to hot, and run the highest octane fuel you can.

Igntion timing: When I get my engine built, this will be the MOST tuned part of the engine. How much retard, and when to dial it in, is THE key factor to getting no detonation, regardless of how much psi of boost, and how much retard with each pound of boost. Many use the Crane unit, and it works, but is limited to 15 psi. To run more boost than that, you will have to pull out too much timing at 15 psi, to run lets say 20 psi. I, as others, have brought up the product J&S safeguard. Technically, this will work wonders for our cars, but could be rather "touchy". It uses an aftermarket knock sensor to detect detonation, and will retard timing on an individual cylinder basis, becuase it will know exactly when and which cylinder just detonated. The J&S will keep ignition timing to the "right before detonation" point in time in the fuel burn, and this has been proven to be the point in which max HP is made, Right before detonation happens. Hopefully now we can discuss detonation and igniton timing in more detail, from those who are boosting using igniton retard units, and what they are doing, how much power they are making, ect.. Hopefully we can all ask questions, and try and learn from eachother here, as no one wants to blow an engine any more than the other guy. The key for all of us should be to retard the timing just enough to not get any detonation. This is where max HP is made. And another side note, detonation does not occur in every cylinder. All the factors listed above can be slightly different, which is why all-cylinder retard can hurt power. Unfortunately, my ignorance on this topic broke my piston Knowledge is power !

13.5 @108 MPH-2.2 60ft(stupid FWD!)
S16G @ 18 PSI/FMIC/Running on MegaSquirt II (Now with sequential
fuel injection)
My webpage: http://eclipsed4evr.home.comcast.net
-1998 Mitsubishi Eclipse RS-T- "Toy"
-1992 Plymouth Laser Turbo AWD(SOLD)
-2000 Honda CR-V(daily)

I agree with you, Matt. Detonation seems to be the big engine killer for us on this forum. It will be in everyone's best interest to find out and experiment with the best method and product to control this. Although I have built internals, I'm always afraid that it could happen again. I believe we've come up with various fuel setups that work great, now let's concentrate more on detonation control. Of course, proper and sufficient fuel setup will always be a major issue.

___________
Kon C

"Sometimes, a man has to do what a man has to do."

I second that one. I just pulled 3 bad pistons from my car. I'm begining to wonder if my cartech FPR is about done for. Either that or I have it hooked up wrong.

Kevin
The old:


The new:

Good idea for a thread Matt. I like that we are starting at the basics here too. So I have a basic idea that I want to hear your comment on as well. One of the things I'm trying to figure out is some kind of base algorithm for spark retard/advance based not only on boost, but rpm. My understanding is that while retarding is good for boost situations, higher rpms require a bit of advance over lower rpms. This is because there is a certain lag time between the spark firing and ignition of the mix in the cylinder. In the case of a lower rpm (and thus slower piston speed) the spark should occur late so that the fuel ignition is in sync with the downstroke. In a higher rpm scenario, you want spark to occur somewhere in the upstroke so that by the time ignition occurs, the piston is starting the downstroke. If timing was kept the same as in low rpms, the piston would be well into the downstroke before the igniton wall hit the piston.

If the timing is not advanced enough, we won't have maximized efficiency and power. Although it's worth sacrificing some hp for safety. Anyways, I was wondering if these ignition systems you guys are running are taking into account rpms at the same time boost. It would be great to just have an equation like f(psi,rpms,intake charge temp)= to begin with. Then I could make an xy coord graph with x-axis as rpms, y-axis as advance/retard, and several different plots on that graph of different psi's. (it'd be a good visual for this kind of stuff) Then we could tune our cars from that starting point, since each engine will be somewhat different.

Oh yea, and who had J&S safeguard on this board?

2gnt: '99 RS-T, killed by a toyota, pending rebuild...
Daily: Volt
Daily #2: '99 EVG ebike- STOLEN by PEDRO

Excellent info there. You are completly right about the timing with low/ high rpms. Lets take an example first of our engines without boost. Our ecu's adjust ign timing based on many factors: rpm, intake air temp, coolant temp, TPS postion, and engine load, and MaP sensor readings. A datalogger will be the most benificial tool ever IMO. Our ecu will advance timing under vacum conditons constantly. When under a minimal engine load, timing will be advanced quite a bit, up to 30+ degrees. When we punch the gas, ecu goes into open loop, and timing is pulled back to around 15 degrees, and may go up slightly (at least this is what i noticed on the datalogger). I strongly believe my episode of my destroying detonation happend in closed loop, part thottle boosting. I hit almost 10 psi in third gear at around 3500+ rpms, with 80% or slightly less throttle. Then I heard the nasty rattling. Then i came to a stop light, and was smoking from the hood out the breather catch can filter i have installed. Why did this happen? In closed loop, the ecu will advance timing to where it gets the most power, and the least amount of emissions (adjusts the A/F ratio to stoich). I think closed loop part throttle boosting is a major concern, as our ecu's don't KNOW we are boosting! Even more improtant for spark retard in this situation. IMO, it will be VERY hard to tell how much timing should be advanced or retarded with rpm alone, as engine load is the key factor to how its done by the ecu. WOT boosting is much easier to come up with, as we can do this with units like the Crane or MSD. Retarding with rpm will most def hurt power over all rpm ranges if used that way. Retarding with boost only is a better way to go IMO, for better power production. Thats what is so nice about factory turbo charged cars. Their ecu's can read boost, and adjust the timing for the load, knock amount, and boost. We need an aftermarket device to simulate this. But now, WE have to figure out how much timing, when to retard, and with how much boost. As rpm increases, the engine load decreases,which leads me to believe most of our engine damage happens at a lower rpm, where timing is the most advanced,with the greatest load, with higher boost. There will be more load in different gears, at diff rpms also. Example, there will be more load at 2000 rpm's in fifth, then at 2000 rpm's in third. Same is true for WOT runs. You will have more engine load at WOT in 5th gear, than at WOT in 4th gear. I noticed this just by reading my o2 voltages on WOT runs. I got .98 v in second gear, and by WOT in 5th gear, i was around .92 v. My fuel pressures were rock steady and at the same psi in all gears. Increased engine load makes the car run hotter, and leaner, because more load needs more fuel. I only wish there was a way to tune our A/F ratios at WOT to engine load, to get a perfect .93v in every gear. At least start out leaner in a lower gear, and then richen it up for higher gears, exactly opposite of what happens now. To me, it just seems that we should not part throttle boost in closed loop, without timing retard, past 5 or 6 psi. WOT boosting, not going over 7 or 8 psi with out minor retard also. How much, well, thats what we need to figure out, to make the max HP we can anyway, without detonating. Some of the dyno numbers posted here, IMO, have been rather low. Esp with the guys running 10 + psi with rpm, and linear boost timing retard units. And also, i am basing my theories and numbers here running stock 9.6:1 comp ratio. Lower comp ratios *should* let us run a little more boost without any retard. Another thing that will make it harder to ignition tune is the A/F ratio. Richer A/F will have a tendancy to detonate less, as leaner A/F can detonate with greater possibility. This leaves a big window as to how much timing needs to be retarded. We need to find the *best* A/F ratio to start with, then tune the igniton retard. They both go hand-in-hand..

I am searching hard for someone with a J&S Safeguard..no luck yet.. Their input and HP numbers with and without it would be perfect. I do plan on getting one of these, and hopefully, if funds permit, i will dyno tune the car at like 9 or 10 psi, with, and without the J&S. I'm sure some interesting HP numbers will result. If i had the 600 bucks, i'd do it right now, on the stock internals.

13.5 @108 MPH-2.2 60ft(stupid FWD!)
S16G @ 18 PSI/FMIC/Running on MegaSquirt II (Now with sequential
fuel injection)
My webpage: http://eclipsed4evr.home.comcast.net
-1998 Mitsubishi Eclipse RS-T- "Toy"
-1992 Plymouth Laser Turbo AWD(SOLD)
-2000 Honda CR-V(daily)

Xtreme, what are the drawbacks for the J&S other than cost? id be willing to try it on the new engine.

1997 Silver RS
Built
T3/T4 BB Turbo
20psi
Most current 1/8th mile time: 8.1@93mph 2.015 60'
1996 Black Supra TT
2004 Silver Snake

>Xtreme, what are the drawbacks for the J&S other than cost?
>id be willing to try it on the new engine.

I have spent some days here researching more about the J&S, looked for testing done on it, ect. It seems it came about for the RX-7 guys. A lot of them use it, and they have relayed info back to the devloper/builder of the J&S. They have come out with the 3rd gen prodcut now, and is pretty versitile. THE most imortant drawback that I can see from this unit, is the sensing of the actual knock. Every engine has a different knock frequency, but they all have a general frequency range of which knock has. Noisy pistons, and other engine noises can confuse the J&S, and cause uneeded timing retard. I read a post or two like this when i was doing my research. This was with the older units also. The idea is great, and for some people who use it, it works excellent for them, has saved their motor many times. Some have probs with it. Its a toss up really. There were more positve comments on it than negative, and most agree that it works at saving their engines from the destructive forces of detonation. I'm still researching the whole topic, and trying to find more info from actual users of the J&S. As of now, I still plan on buying one. Whats another 600 bucks?? hehe...oh well..

13.5 @108 MPH-2.2 60ft(stupid FWD!)
S16G @ 18 PSI/FMIC/Running on MegaSquirt II (Now with sequential
fuel injection)
My webpage: http://eclipsed4evr.home.comcast.net
-1998 Mitsubishi Eclipse RS-T- "Toy"
-1992 Plymouth Laser Turbo AWD(SOLD)
-2000 Honda CR-V(daily)

It seems to me that the absolute best solution to controlling detonation would be a full standalone engine management system, ie Haltech or TEC3. With the Tec3, you can retard timing based on rpm/boost,even adjust individual cylinder timing. Granted, it is pricey at about 2500 fully installed, but when you figure 500 for a boost controller, 400+ for an ignition amplifier, 500 or whatever for a boost retard box,500 for a datalogger, you start to see the value of having all those features in one box. Couple that with the tunabilty of a wideband 02 and the advantage is clear. This is DEFINATELY the way i'm going to go once i go turbo.

**************
Fucking Kangaroos.
**************

I am quite interested in the J&S as well. The Miata guys have been using this product for some time now. We may want to head over to some Miata forums and talk to them.

I got this froma Miata forum.

"Normally, the J&S Yellow wire taps into the airflow signal. The unit is then armed to detect knock when sufficient airflow is achieved.

The mass air signal on 1.8L engines increases with increasing airflow. The J&S becomes armed when the voltage exceeds 2.75 volts.

On a 1.6L, the voltage decreases with increasing flow. The unit is armed when the voltage drops below 0.8 volts.

When you switch to a Link, you need to set the J&S up as a 1.8L, and connect the J&S Yellow wire to the MAP signal. The J&S will arm when the MAP voltage exceeds 2.75 volts, and the RPM exceeds 1250.

Temporarily disconnecting the Yellow wire will allow the unit to self arm, but to test for knock retard, make sure the RPM exceeds 1250."

What voltage dose our map give? If we use a Missing Link will our map be able to activate the J&S?

>To me, it just seems that we
>should not part throttle boost in closed loop, without
>timing retard, past 5 or 6 psi. WOT boosting, not going over
>7 or 8 psi with out minor retard also.

I tend to agree with you on this one. It's a big hurdle - using a non-turbo ECU with a turbo. Every turbo kit already clamps the MAP voltage or modifies it with something like the missing link. The open/closed loop timing curve is not addressd by any kit(like it is with the stock turbo ECUs). I wonder if we could fashon a sensor that would somehow 'clamp' the ECU to open loop after seeing 5 or 6 pounds...much like the device that Corbin designed to fool the S-AFC to run from boost pressure. Perhaps it could intercept/control the TPS voltage. When it sees 5 pounds and TPS<80% then clamp the TPS to 85%...but as soon as the actual TPS hits 85% then it relinquishes voltage control back to the actual TPS sensor. You can't just blatently hold the TPS at 85% at WOT, that would be no good. It would have to take boost pressure AND the TPS voltage BOTH as inputs and output an 'open loop' TPS voltage when nessicary. Would there be any drawbacks with a sensor like this? What are they?

As far as the retard at higher boost, you would still need a Crane or Safegaurd or something like that.


ride__________95 Eclipse RS : 5 speed
power________Gude cams : AFX UDP : ram air : test pipe : Thrush glasspack
suspention___BOMZ F/R upper strut bars : ES inserts
sound________Kenwood KDC 5000 : Audiovox 8" sub toob - no sub amp(damnit!)
shizzle_______AutoCommand remote start : dual air horns
incomming___Hurricane F/R lower strut ties : Jeep TB : Field SFC Hyper-R : GST catback

95 Eclipse RS : 5 speed
14.76 @ 94.72mph
Jeep TB writeup - http://www.dimensia.com:81/jimbo/JeepTBfor2gnt.html

The J&S uses our map, and tps, the provided knock sensor, and the stock ignition coils. Here is a link to the Subaru diagram, which will be nearly identical for our cars. http://www.jandssafeguard.com/SubaruInstall.html

Metaljim, you have an EXCELLENT idea there. I am going to think more about this, and reply back here on my thoughts..time for more research

13.5 @108 MPH-2.2 60ft(stupid FWD!)
S16G @ 18 PSI/FMIC/Running on MegaSquirt II (Now with sequential
fuel injection)
My webpage: http://eclipsed4evr.home.comcast.net
-1998 Mitsubishi Eclipse RS-T- "Toy"
-1992 Plymouth Laser Turbo AWD(SOLD)
-2000 Honda CR-V(daily)

Ok, here are some thoughts on metaljim's idea. Anyone please step in with your thoughts about any of this also.

Fooling the ECU into going into open loop with boost is a great idea. BUT, it may hurt our low boost(1-6 psi) power. Our engines are built and designed to be VERY detonation proof. The actual shape, design, and the excellent flow characteristics of our cylinder head helps denote detonation in itself, which is why we can run almost 8 psi without getting detonation. I noticed on the datalogger that WOT timing advance stays pretty close to 15 degrees. I think, just by how the car feels, that this is almost PERFECT timing advance running upwards of 8 psi, on stock 9.6:1 compression. The car just pulls excellent with that boost pressure, and ignition timing (remember, we are running 93 octane gas here, as must at 8 psi). The reason i say this, is becuase detonation seems to set in right after 8 psi, as I and others have blow our stock pistons at anything over this (even with slightly rich A/F ratios). NOW, part throttle boosting in closed loop, seems to be right on power wise, using the stock ecu timing advance to upwards of almost 30 degrees! With this much advance, anything over 6 psi may cause detonation,in closed loop. So now running 1-6 psi in closed loop is making great power, without detonation, becuase of our great cumbustion chamber design. Now, if we were to fool the ECU into going into open loop at lower boost, say 1-6 psi, IMO, it would really hurt our HP in low boost. But we have to think about how long we are actually in low boost in closed loop. Not long at all. It takes quite a bit of easy throttle to build 7+ psi of boost without going into open loop (80% + throttle). I did that one time hit almost 10 psi, but it had just went out of closed loop. It was mearly a second. IMO, it would be best to START timing retard at lets say 6 psi, when in closed loop ONLY. We dont need any timing retard with boost lower thatn that, if we did, we would loose big power, since detonation at that boost or lower doenst really happen with a lot of timing advance. If we saw 15 degrees of timing at 1-6 psi of boost, it would def hurt HP, in big way IMO. If we could retard boost starting at 6 psi in closed loop, up to where it goes into open loop, that would be perfect. That would protect our engines from 6 psi to 10 psi, if we could get boost that high in closed loop)). Then when the ecu goes into open loop, only start retarding starting at 7 or 8 psi, and on up from there. This way, we keep our low boost, closed loop power , and very little chance of detonation if we can actually get boost to go higher in closed loop. Then when we get the ecu to go into open loop, timing will again start to retard once more, starting at 8 psi on up. Does this make sense? Its almost going to be "easier" to keep a watch on our boost gauges to not let part throttle boost go above 6 psi in closed loop, rather than trying to figure all this out, let alone finding the proper retard modules and electronics to make it work. After we hit that 6 psi, just puch the gas to the floor, or far enough to get the ecu to go into open loop. This way, timing retard units that can retard with boost, will work if we set them to start retarding at 8 psi and higher. That just brings us back to where we started We NEED at least a unit that will retard timing when under boost. But it needs to be versatile enough to only start at 8 psi and up, where we only need it. It could then be fine tuned with an rpm based retard as well, but much dyno time to do that properly. I still think retarding only with rpm's is not the best way to go for power production. We just plain dont need it. Not at lower boost. Time once again for more research..I am determined to find the right product that will work for us MSD makes a boost only retard unit, i am looking into that, as it can be had for 300 or less. Its a start. I earnestly believe there is a way we can do this, without shelling out big bucks for a stand alone EMS, and at the same time, make EXCELLENT HP, without blowing up our little 420A's

EDIT: Ok, i see what metaljim is saying, i didnt understand at first. But you say that only start retard in closed loop at 6+ psi of boost, which is what i was tyring to say also. I still need to think about this some more really

13.5 @108 MPH-2.2 60ft(stupid FWD!)
S16G @ 18 PSI/FMIC/Running on MegaSquirt II (Now with sequential
fuel injection)
My webpage: http://eclipsed4evr.home.comcast.net
-1998 Mitsubishi Eclipse RS-T- "Toy"
-1992 Plymouth Laser Turbo AWD(SOLD)
-2000 Honda CR-V(daily)

is it true that the crane ignition only allows for timing retard up to 15psi?

Ok, heres another idea What if we could get a timing retard unit to have 2 diff settings we could switch from. It could be switched from one setting to the other by TPS location. So, for example, we could have settting 1 to start retard at 80% or less throttle, which is closed loop. Start retard in at 5 or 6 psi, and let it go up in retard to as high as we can, as long as it stays in closed loop. THEN, when TPS is 80% or greater, the second setting activates, and retard can start in at 8 psi on up. This way, if we are mashing the gas from a stop, the ecu will be in open loop right away, with 0 boost. Setting 2 will be first activated. That way, we can build most power without retard until 8 psi. Then the retard kick in to prevent detonation. Now lets say we take off from a stop lighlty, in light boost. SEtting 1 will be active, and will only start retard with 5 or 6 psi on up, just until it switches over to setting 2 retard values. Does this make sense to anyone? Logically, it sounds right..Actually, the J&S Safeguard may do this..not sure... Ideally, this is what we need. What do you guys think?? I just may try and contact the actual designer/builder of the J&S to see what he thinks. You never know, he may be able to design one just for us

Ok, here is a quote from J&S safeguaurd for the unit that will work for us: "If the unit is connected to the TPS wire, the unit will pull the TPS signal to 5v at 0 psi. This should kick the ECU out of closed loop operation." This will work great IMO. That way, WHENEVER we are boosting, the ecu will be in open loop, and we can start retarding at whatever psi we want, and we can adjust how much retard per psi of boost we want. The only drawback is that we will see 15 degrees of advance at lower boost, which may hurt HP in low boost. But when racing, we arent there for very long anyway.. Under light throttle boost, HP and pull may be hurt too though... But my theory does make sense. Whenever i boost lightly from a stop, in closed loop, the car responds and pulls very well. If I go from a stop and use a lot of gas pedal, the car takes longer to get faster, ie.. there is less spark advance in lower boost. I just wish there was compromise like my 2 stage idea...

13.5 @108 MPH-2.2 60ft(stupid FWD!)
S16G @ 18 PSI/FMIC/Running on MegaSquirt II (Now with sequential
fuel injection)
My webpage: http://eclipsed4evr.home.comcast.net
-1998 Mitsubishi Eclipse RS-T- "Toy"
-1992 Plymouth Laser Turbo AWD(SOLD)
-2000 Honda CR-V(daily)

another thing to consider for you "weekend warriors" that wanna run a little higher boost at the track and keep away detonation, RACE GAS. Xtreme, keep me/us informed of your findings regarding the J&S unit, im very interested. this is also a product Honda owners have been using for quite some time. my friend has one on his JRSC Si.

1997 Silver RS
Built
T3/T4 BB Turbo
20psi
Most current 1/8th mile time: 8.1@93mph 2.015 60'
1996 Black Supra TT
2004 Silver Snake

I like your 2 stage idea too, but realistically, it is only most beneficial to people with a stage 2 turbo setup. This is because 6 psi is nearing your max boost of 8-10 psi. You will feel a noticable difference between 6 psi at 30 deg of advance and 6 psi with 15 deg of advance. The thing is though, the people who really need a setup like this will already have forged internals and the proper modifications to support 15+ psi. When daily driving with a car that can run 15 psi, you will most likely be seeing 10 or so psi in closed loop mode at an average acceleration. At 10 psi, 15 deg of advance is near perfect timing from what I've gathered on 8.6:1 pistons. My point is that when you are running that much boost, are you really going to care about your combustion efficiency at 6 psi?? When you are running the car hard, you will only be in that range for less than a second, and when you are just cruising around, if you want more acceleration, just move the pedal down a bit to where the fuel and air combust more efficently (8-10 psi). IMO, the J&S is the way to go for timing control, hands down. At least from everything else I've looked into (that includes standalones). Standalones are waaay sweet, but the majority of them still require you to set the timing yourself at various amounts of boost/RPM. This is more versitile than say a Crane or MSD ignition, but basically still leaves room for error because a person has to tune it. Obviously tuning on a wideband dyno will help, but once you set your timing, it wont adjust for different factors like air intake charge temp and atmospeheric pressure, etc... The J&S will control your timing electronically like a mini-ecu for timing alone. I think the idea of altering the TPS voltage when it detects boost to put the car in open loop mode is an excellent idea. On top of adding safety, it will make the boost transition much smoother.

Remember, from the factory, the car is supposed to see around 15 degrees of advance at 0 vac, not 10 psi It is also supposed to be at 30 deg of advance in low vac conditions, not 6 psi of boost. I realize, that the car is being on the safe side there, but being on the safe side is what saves you money, time and cuts (those of you who have rebuilt before know what I'm talking about) and gets you hundreds of thousands of miles on the motor. Pushing the timing to the max without detonation is definately the most efficeint means of gaining hp and torque, but its risky. Personally, I would rather pull timing a bit more for added safety and add a few pounds of boost to make up for the difference of power.

Matt
1995 Eclipse GS
2.0L, S16g Turbo, 8 Injectors, 26psi

1998 Eclipse GSX
2.3L Stroker, AEM EMS Converted to Speed Density, FP3065 Turbo, 35psi , and so on...

First, I'll agree that clamping to open loop at the first sign of boost will hurt low boost performance. I just don't like that idea at all. Initially the 2 stage approach sounds like it would work well. It looks like the MSD Programmable DIS-2 could handle the 2 stage setup your talking about. It has a Multi-Step retard feature:

<MSD_QUOTE>
Multi-Step Retard: Three separate stages of retard can be activated by either rpm or a separate activation wire. This is perfect for all nitrous applications. Programmable from 0°-15° in 0.1 degree increments within 800 - 15,000 rpm in 100 rpm steps.
</MSD_QUOTE>

A switch could be fashoned to activate the appropriate timing maps. You could have a map for open loop and a map for closed loop. This is where the conversation goes back to my idea...but I'll save my comments on this "switch" for the end of this post(bear with me here).

It also looks like the programmable DIS-2 would handle the different loads(like you were talking about earlier in the thread) that the different gears see with the Gear RPM and Retard feature:

<MSD_QUOTE>
Gear RPM and Retards: Program a different rpm shift point for each gear as well as a retard for every gear change.
</MSD_QUOTE>

Actually just reading about it, it looks like a great ignition. You can program the boost timing curve. It can handle up to 45psi. You can adjust individual cylinder timinig. It doesn't support knock sensative timing retard. I know jamesman has one. I think a couple of people have it. It's $420 at Summit.

Ok now back to the switch.

Lets call it a loop controller instead of MetalJim's idea...well we could call it that too, but I'll call it a loop controller. I've thought about it a bit more.

It still works exactly like I said before, clamping the TPS to 85% when it hits a particular boost threshold, forcing us into open loop until the actual throttle position goes above our clamp voltage(85%), where we would relinquish TPS voltage control back to the TPS sensor. This would give us the open loop's more "boost friendly" timing curve. It could be set to clamp at any particular boost level - I'll call that the boost threshold. The boost threshold on the controller would have to be adjustable. Maybe you would want to set it to 6. What if you're running a higher compression, like 11.5:1 or 12.5:1. With that kind of compression, you would definately want to pop into open loop at a lower boost, maybe like 1-3 pounds, or maybe the first sign of boost. I think this would be perfect for stock, DIS-2, Crane, or Safegaurd ignitions. It gives you "boost friendly" timing at a particular boost level. You can use the stock open/closed timing curves up until your loop controller's boost threshold, then it switches over to open loop(lets say 6 pounds in your case). You can take advantage of the safer open loop curve until you need to start to retard timing(lets say 8 pounds in your case). Then you can use an aftermarket ignition to retard the boost from there. AT THE VERY LEAST, you'll have safe timing at any throttle position AND if you use a ignition retarding unit - you'll always be retarding the open loop curve because the retard starts well above the loop controller's boost threshold. Its more like a safety device for situations like the one that you ran into where you went into closed loop at 10psi.

Well what about staging open and closed timing curves with something like the Programmable DIS-2 unit? Lets take your switch based solely on TPS. At what voltage do you switch over from open to closed loop? The switch would have to calibrated to be very precise. It would have to be at the exact moment of the switchover, otherwise its just useless. It's not like theres a wire on the ecu that tells us weather or not we're in open loop...or is there? I think the only way to ensure that the switch will give a correct open/closed loop signal is if it controls weather or not the car is in open or closed loop. Thats fine. My loop controller(as it stands) doesn't exactly work for that situation either. But lets make a more complicated loop controller, one that can tell us without a doubt that we're in open loop. This one is going to have to jump to open loop when we reach a particular throttle angle, lets say 75%. When we hit 75%, we just automatically clamp the TPS to 85%, throwing us into open loop. Then when the throttle angle reaches our clamping level we relinquish control to the TPS sensor. Also, as you back off below 85%, you have to keep the controller's TPS signal clamped to 85% till the sensor goes below 75% then you can relinquish control back to the TPS sensor. So the controller works exactly the same way, except that it will also put us in open loop right before the stock computer would normally do it. You'll still have a boost threshold and anything above that threshold will throw you into open loop. The loop controller would live up to it's name. It would control every aspect of switching between open and closed loop operation. At that point, you could have a wire running out of it that could tell something like the programmable DIS-2 unit weather we are in open or closed loop WITH AUTHORITY. I'm not sure how practical or pragmatic it would be to have this much feedback and control over the ECU's loop state. I think that with the simple loop controller(boost threshold activated only), you could get away with using a much simpler retard unit without having to worry about what state the ECU is in. I guess my argument is that you could use the programmable DIS-2 with the simple loop controller(the one described in the previous paragraph) and you wouldn't need to have different curves for open and closed loop operation. Just set the boost threshold right below your critical closed loop pressure(6 pounds in your case) and then pull timing at your critical open loop pressure(8 pounds in your case).

Ok, it sounds like I just convinced myself out of the usefullness of a more complicated loop controller. I think the simple loop controller is all anyone would need. I'm gointg to try to make my questions a little more specific this time. From some of the comments, it sounds like the loop controller shouldn't activate that much. Mostly I'm concerned with our computer's "learning" abilities. What if the boost threshold was lower(like for my high compression examples) and it does activate often? Does the computer learn timing curves like it does with fuel trim? Would there be any drawbacks(while using a loop controller) with the amount of time the computer is "learning"?


ride__________95 Eclipse RS : 5 speed
power________Gude cams : AFX UDP : ram air : test pipe : Thrush glasspack
suspention___BOMZ F/R upper strut bars : ES inserts
sound________Kenwood KDC 5000 : Audiovox 8" sub toob - no sub amp(damnit!)
shizzle_______AutoCommand remote start : dual air horns
incomming___Hurricane F/R lower strut ties : Jeep TB : Field SFC Hyper-R : GST catback

95 Eclipse RS : 5 speed
14.76 @ 94.72mph
Jeep TB writeup - http://www.dimensia.com:81/jimbo/JeepTBfor2gnt.html

"Ok, it sounds like I just convinced myself out of the usefullness of a more complicated loop controller. I think the simple loop controller is all anyone would need. I'm gointg to try to make my questions a little more specific this time. From some of the comments, it sounds like the loop controller shouldn't activate that much. Mostly I'm concerned with our computer's "learning" abilities. What if the boost threshold was lower(like for my high compression examples) and it does activate often? Does the computer learn timing curves like it does with fuel trim? Would there be any drawbacks(while using a loop controller) with the amount of time the computer is "learning"? "

From what i understand, *please* someone correct me if i'm wrong, that the ONLY thing that tells our ecu to go into open loop is the TPS sensor location, eg.. TPS voltage. I think we need to be more concerned with part throttle, low boost, closed loop boost more than we think. I know, for me anyway, that I spend WAY more time in closed loop boost then at WOT open loop boost. Only when racing, or at the track do i go to full WOT boost. Unless some of you guys like to be speed demons when daily driving.. IMO, if we run the J&S safeguard, 15 degrees of timing at low boost will give us very little power, esp for light acceleration. If you think about it...We are going from almost 30 degrees of timing advance at 1 or 2 hg's of vacum, to an instant 15 degrees of timing advance at 0 psi of boost. IMO, we wont feel any real noticable "pull" until 3-5 psi of boost,to make up for the less timing advance in low boost. Daily drivabilty will for sure be affected, and lower boost will most def just seem like a waste of gas. We will have to use more throttle to boost more psi to get moving. With me so far?

This point makes me think of why running a higher compression motor with the J&S more advantageous. That way, when under low boost, we will make more HP with less timing (15 degrees) than stock compression. Then we can set the J&S to start retard in at like 3 or 4 psi of boost, and on up. Remember, the J&S can pull upwards of a full 26 degrees of timing retard, which would be PLENTY of retard for a high compression motor running up to 20 psi IMO. I think Metaljim and I are coming to the same conclusion of a dual stage retard, with one set of values for closed loop, and antoher set for open loop. Now factor in that most of the "built" motor guys are running lower compression, that the J&S will hurt low boost performance, and driveabilty even MORE than the stock compression ratio, as lower compression makes less HP per each PSI of boost. We would then need to boost even MORE, lets say 5-6 psi in light throttle to feel any big power pulling of the car. 15 degrees of timing advance at lower boost is not at all good for power. ESP for 8.5:1 engines. I stil come back to my idea, of closed loop retard starting at 5 or 6 psi for stock comp motors, and 3 or 4 psi for low comp motors, then a second retard setting of open loop retard at 8 psi on stock comp, and 9 or 10 psi on low comp. The MSD DIS2 looks like a good candidate, but the whole switching thing is the question. How does it switch between the 2 settings? From what it says above in the quote, its great for N2o. This means that sending a 12v signal from a soleniod can put the MDS-2 into its other setting. If we need to switch using TPS voltage, its not going to happen, not without metaljim's "loop controller". Maybe the MSD can actually do this, I'm just not to knowledgable about that unit yet. The J&S still seems a better way to go..ESP with the knock retard feature. As Matt_95tgs pointed out, different variables will affect detonation, and when it can occur. Timing needs to be adjusted for that, automatically, which the J&S does, not like the MSD DIS2. The MSD cant detect knock, and pull timing, which is detramental for running high boost, lets say on a really hot day.

Now, if we could get the J&S to go into open loop at MORE than 0 psi, lets say at 5 or 6 psi, then that would be ideal. I dont think it can at this time though. This way, we can still maintain our closed loop, part throttle boost power, with 30 degrees of timing. Then have the ecu go into open loop at 5 or 6 psi, at 15 degrees of timing, and then start its actual retard at 8 psi and on up. This might be able to be done with something as simple as a manual boost controller going into the J&S. That way, when we are at 5 or 6 psi, the J&S will only see 0 psi, and only then will it go into open loop ecu timing. Boost retard and how much retard with boost is fully adjustable with the J&S using a dash mounted controll knob.

13.5 @108 MPH-2.2 60ft(stupid FWD!)
S16G @ 18 PSI/FMIC/Running on MegaSquirt II (Now with sequential
fuel injection)
My webpage: http://eclipsed4evr.home.comcast.net
-1998 Mitsubishi Eclipse RS-T- "Toy"
-1992 Plymouth Laser Turbo AWD(SOLD)
-2000 Honda CR-V(daily)

<<<I think we need to be more concerned with part throttle, low boost, closed loop boost more than we think. I know, for me anyway, that I spend WAY more time in closed loop boost then at WOT open loop boost. Only when racing, or at the track do i go to full WOT boost.>>>

I agree with XtremeRS. I rarely ever got WOT during regular driving. The Super16g is a little slow to spool, but when it hits full boost there better not be anything in front of you! With all the traffic in the city, partial throttle boosting is usually all my car sees on a daily basis.

Looking at this from another angle, we're all discussing different ways of making our ECU's work like the ones in the factory turbo cars. Well, since AFX is manufacturing ECU's for our cars now, could they make one that is capable of reading boost pressures and adjusting timing accordingly?

You are not your job.
You're not how much money you have in the bank.
You're not the car you drive.
You're not the contents of your wallet.
You're not your fu**ing post count.

97 Eclipse GS - *SOLD*
01 Audi A6 2.7T
01 YZF-R6

I think you guys have come up with some pretty good ideas, and I believe the only way we can achieve timing/boost/knock issue is to somehow modify the ecu, just like Boosted GS mentioned. This type of "total" control can (probably) only be achievable with an electronic processor, such as a reprogrammed ignition/fuel map.

Since, Howell Automotive has figured out how to reprogram our ecu, it will be just awesome if they can "imitate" the 4G63's ecu to the 420A ecu; or, if someone could figure out how to modify the turbo ecu to fit our cars--without not having to replace the harness, etc, that will be the best option. Any thoughts on this?

I think it will be difficult to try to imitate the turbo ecu with other add-ons, such as the J&S, aftermarket ignitions, Accel DFI, etc, unless J&S will research that for us. I'm sure it will be possible, but there're just too many parts to worry about (in terms of diagnosing problems, etc). The Accel DFI is prety versatile, but no one has been able to configure it to control timing, in addition to the fuel maps (for the 420A).

___________
Kon C

"Sometimes, a man has to do what a man has to do."

>I think you guys have come up with some pretty good ideas,
>and I believe the only way we can achieve timing/boost/knock
>issue is to somehow modify the ecu, just like Boosted GS
>mentioned. This type of "total" control can (probably) only
>be achievable with an electronic processor, such as a
>reprogrammed ignition/fuel map.
>
>Since, Howell Automotive has figured out how to reprogram
>our ecu, it will be just awesome if they can "imitate" the
>4G63's ecu to the 420A ecu; or, if someone could figure out
>how to modify the turbo ecu to fit our cars--without not
>having to replace the harness, etc, that will be the best
>option. Any thoughts on this?
>
>I think it will be difficult to try to imitate the turbo ecu
>with other add-ons, such as the J&S, aftermarket ignitions,
>Accel DFI, etc, unless J&S will research that for us. I'm
>sure it will be possible, but there're just too many parts
>to worry about (in terms of diagnosing problems, etc). The
>Accel DFI is prety versatile, but no one has been able to
>configure it to control timing, in addition to the fuel maps
>(for the 420A).


Well thinking about the "new ecu" idea, i think that it would be very limited in what timing curves that it could produce. With many people here running different turbos, and custom setups, the "new" ecu may not give enough room for adjustment. This is where the adjustability, and versaility of the J&S can come into play. If this unit does indeed let us run a "user adjustable" boost pressure point for open loop operation, that will be THE answer to all of this. We can then adjust the amount, the exact psi, and when to pull timing when in open loop mode. IMO, thats what we need. Yes??

13.5 @108 MPH-2.2 60ft(stupid FWD!)
S16G @ 18 PSI/FMIC/Running on MegaSquirt II (Now with sequential
fuel injection)
My webpage: http://eclipsed4evr.home.comcast.net
-1998 Mitsubishi Eclipse RS-T- "Toy"
-1992 Plymouth Laser Turbo AWD(SOLD)
-2000 Honda CR-V(daily)

UPDATE: I spoke with John Rizzuto today, the designer of the J&S Safeguard. This unit will have 2 extra switches on it, to do whatever we want, or more accurately, what can be "programmed" into by John. It will fully work with my last idea. He can program the unit to not let the ecu go into open loop until a set, desired boost level, using the extra dipswitches. With several configurations available, we can have the J&S go into open loop at lets say 5 psi. Then after 5 psi, the ecu goes into open loop, and our timing goes back down to around 15 degrees, up until we set it for whichever boost amount we want to start boost retard at, lets say 8 psi. Lets say you have a low compression motor. Use another switch setting to have the ecu go into open loop at lets say 7 psi. I think this will be an EXCELLENT way to go if this works like intended. I informed John about this site, this thread to be exact. I'm waiting for his words on this topic, as i'm sure we all want to hear about what his product can really do for us.

13.5 @108 MPH-2.2 60ft(stupid FWD!)
S16G @ 18 PSI/FMIC/Running on MegaSquirt II (Now with sequential
fuel injection)
My webpage: http://eclipsed4evr.home.comcast.net
-1998 Mitsubishi Eclipse RS-T- "Toy"
-1992 Plymouth Laser Turbo AWD(SOLD)
-2000 Honda CR-V(daily)

Well, it sure is nice to see such a constructive thread started to solve this problem. I am more than anxious to hear from John to see what the J&S's complete list of capabilities are. From what you have said so far Matt, you know I'm sold (actually I was sold on it before this post started haha). I agree that the perfect solution would be to automatically kick the car into open loop mode at whatever boost level you have him set it at. As far as timing is concerned, this would make our timing curves very similar to that of a 4g63 ecu. It will be a nice, smooth curve without sacrificing low boost power. Thumbs up here, good thinking fellas.

Matt
1995 Eclipse GS
2.0L, S16g Turbo, 8 Injectors, 26psi

1998 Eclipse GSX
2.3L Stroker, AEM EMS Converted to Speed Density, FP3065 Turbo, 35psi , and so on...

It will fully work with my last
>idea. He can program the unit to not let the ecu go into
>open loop until a set, desired boost level, using the extra
>dipswitches. With several configurations available, we can
>have the J&S go into open loop at lets say 5 psi. Then after
>5 psi, the ecu goes into open loop, and our timing goes back
>down to around 15 degrees, up until we set it for whichever
>boost amount we want to start boost retard at, lets say 8
>psi.

Matt 98RS, with that kind of interest from J&S, it does seem to be our best alternative to a 4G63-like ecu, and for about $600. I really hope this idea will become a finished product because I want one!

___________
Kon C

"Sometimes, a man has to do what a man has to do."

>Matt 98RS, with that kind of interest from J&S, it does seem
>to be our best alternative to a 4G63-like ecu, and for about
>$600. I really hope this idea will become a finished
>product because I want one!

this thread is really good!

i would be great if hahn had so type of service to get our ecu reprogrammed to work with there kits.

New Car:
2004 350z base, Nismo CAI, pioneer avic-n1 (dvd, cd, navi)



Old Car:
1998 GS with hrc stage 2, HID 6000k conversion kit, AEM UEGO wideband, sfmu, ml, prokits, Greddy warning gauges: egt, boost gauge, and oil pressure, apexi tt, haydans tranny cooler, costum dp, groundwires, dynotune fp gauge. gst muff, turbo spoiler
Boostin since Aug 03.

nothing like driving with the windows down and the music low: i love hearing the turbo spool, swwwhhhttt!!!!

it sucks you just went thorugh a piston or two. yes, detonation is bad. No, detonation is not that hard to avoid in most situations. if you don't lean your car out a lot with an afc, or an afr, or any other kind of piggy back device to run boost, then once you hit 0 atmospheric pressure, your ignition timing should hit 18 to 15 degrees advance on the spot. MAYBE 21......no higher. if it doesn't, you are probably using an afc or some other device to make the ecu not see "full" voltage from the map sensor. it is perfectly safe to run over 8 psi of boost with 21 degrees of spark advance. The stock thermostat is relatively high for bosted applications, but it has been proven to work. a 160, 170, or 18 degree thermostat would work better, but the 195 does do the job. several cars boost on it and have boosted on it for quite some time. you ABSOLUTELY ABSOLUTELY ABSOULTELY CAN'T trust the oxygen sensor voltage alone. you will ABSOULTELY blow your shit up if you do. I remember helping 96venger tune his car. he had the corbin meter in his car, and it was reeding .999 to .998 volts when we first got his car runnign with the 440 cc injectors. at .999 volts, the car shouldnt' even be "running".........let alone have a huge hill in the middle of the air/fuel ratio curve. so we put the 2.72' disk in his car, and richened up the middle enough to flatten it out on the scale to around 11.5 :1 across the board from the time the pedal went full throttle to the time we let off.........the voltmeter said .99 to .98 all the way across..........guess what the afc said........... .96 to .95 all the way across. if you want to push your car past 12 psi, you REALLY need to hav eyrou car tuned with multiple instruments (i.e. egt gauge, wideband o2 sensor, and if possible aftermarket knock sensor). the factory oxygen sensor is NOWHERE NEAR accurate enough to keep your car runnin if you push it. if you run mroe than 12 to 18 psi, you really need to be in the 11.5 to 11.3 range in air/fuel ratio. if you run more than 18 psi, you really need to be in the 11.3 to 11.0 range. if you run less than 12 psi, you can probably get away with running at 12.0 air fuel ratio, but not for long if your car isn't consistant (due to a poor fuel pressure regulator). if you run leaner than this, you "will" be buying new pistons, and if you run mroe than abotu 21 degrees of timing at ANy of the above suggestions, your pistons and head and cylinder walls WILL look like someone went crazy with a tiny chizel around every corner and edge fo yoru combustion chamber and pistons. just keep timign around 18 to 20 degrees max under boost, and boost pressure under 12 psi on stock pistons and under 20 psi on aftermarket forged pistons on 93 octane gas, and you will be fine. if you don't.......you will be building another engine.......trust me, I know.

oh, and also, how can the J and S safegaurd retard each cylinder's ignition firing when on our cars 2 cylinders fire at a time (waste spark). that doesn't add up to me.

A.D.P.
"...If you do too much, people become dependant. If you do to little, people loose hope. If you do it right, people won't be sure you've done anything at all."
bring it on............

A.D.P.
"...If you do too much, people become dependant. If you do to little, people loose hope. If you do it right, people won't be sure you've done anything at all."
bring it on...........

From the way that it's been explained to me, our cars don't fire 2 cylinders at a time. The spark does fire, but one of them is on the compression stroke and the other is on the exhaust stroke. I havent visually checked the cam lobes to confirm this myself, but that's what I hear... When the J&S knock sensor detects knock on a cylinder, it knows when that piston will be on the compression stroke and when it is on the exhaust stroke. Therefore, it knows which spark to retard (the detonating cylinder on the compression stroke) and which spark to leave alone (the other cylinder not detonating). This goes for both cylinders 1 and 4 and cylinders 2 and 3. That is the only way that they can pull timing on an individual cylinder basis with a 2 coil ignition.

You said that both pistons fire at the same time... Are you absolutely sure about this, because if that is the case, then it would seem to me that individual cylinder timing would be out of the question, and that would suck.

Matt
1995 Eclipse GS
2.0L, S16g Turbo, 8 Injectors, 26psi

1998 Eclipse GSX
2.3L Stroker, AEM EMS Converted to Speed Density, FP3065 Turbo, 35psi , and so on...

hmm. no. the car has to fire both 2 and 3 or 1 and simultaneously. there is no way to retard 1 cylinder at a time without retarding both, wether it be while one is on compression stroke and one is on exhaust stroke or vice versa. both fire at the same time. that is why there are only 2 trigger wires on our coil packs.

A.D.P.
"...If you do too much, people become dependant. If you do to little, people loose hope. If you do it right, people won't be sure you've done anything at all."
bring it on............

A.D.P.
"...If you do too much, people become dependant. If you do to little, people loose hope. If you do it right, people won't be sure you've done anything at all."
bring it on...........

>hmm. no. the car has to fire both 2 and 3 or 1 and
>simultaneously. there is no way to retard 1 cylinder at a
>time without retarding both, wether it be while one is on
>compression stroke and one is on exhaust stroke or vice
>versa. both fire at the same time. that is why there are
>only 2 trigger wires on our coil packs.

Yes, true, let me explain how the J&S retards per cylinder>

Ok, let me explain this a little more, using how the J&S retards spark on and per cylinder basis. Yes, cylinder 1 and 4 share the same coil/ and spark as does cylinder 2 and 3. Both sets fire sparks at the same time. If cylinder 1 is on the compression stroke, then cylinder 4 is on the exuast stroke. So cylinder 1 fires, as does cyinder 4. Power is made by the spark in cylidner 1 because its on the compression stroke. Spark is wasted in cylinder 4, since its on the exaust stroke. NOW, lets say when cyl 1 fired, it detonated. The J&S knows this cyl detonatied becuase the sensor read the knock, and it knew which coil trigger wire just fired. Now the unit will retard cylinder 1 NEXT TIME IT FIRES. The J&S knows that we have 2 coils. The unit knows that the exact next cylinder to be fired from the cyl 1 coil is cyl 4. So it SKIPS this trigger signal, and waits for the next trigger signal, and THEN it retards that signal, which is cyl 1. Make sense?? So we can retard on a per cylinder basis.

13.5 @108 MPH-2.2 60ft(stupid FWD!)
S16G @ 18 PSI/FMIC/Running on MegaSquirt II (Now with sequential
fuel injection)
My webpage: http://eclipsed4evr.home.comcast.net
-1998 Mitsubishi Eclipse RS-T- "Toy"
-1992 Plymouth Laser Turbo AWD(SOLD)
-2000 Honda CR-V(daily)

>it sucks you just went thorugh a piston or two. yes,
>detonation is bad. No, detonation is not that hard to avoid
>in most situations. if you don't lean your car out a lot
>with an afc, or an afr, or any other kind of piggy back
>device to run boost, then once you hit 0 atmospheric
>pressure, your ignition timing should hit 18 to 15 degrees
>advance on the spot. MAYBE 21......no higher. if it
>doesn't, you are probably using an afc or some other device
>to make the ecu not see "full" voltage from the map sensor.
>it is perfectly safe to run over 8 psi of boost with 21
>degrees of spark advance. The stock thermostat is
>relatively high for bosted applications, but it has been
>proven to work. a 160, 170, or 18 degree thermostat would
>work better, but the 195 does do the job. several cars
>boost on it and have boosted on it for quite some time. you
>ABSOLUTELY ABSOLUTELY ABSOULTELY CAN'T trust the oxygen
>sensor voltage alone. you will ABSOULTELY blow your shit up
>if you do. I remember helping 96venger tune his car. he
>had the corbin meter in his car, and it was reeding .999 to
>.998 volts when we first got his car runnign with the 440 cc
>injectors. at .999 volts, the car shouldnt' even be
>"running".........let alone have a huge hill in the middle
>of the air/fuel ratio curve. so we put the 2.72' disk in
>his car, and richened up the middle enough to flatten it out
>on the scale to around 11.5 :1 across the board from the
>time the pedal went full throttle to the time we let
>off.........the voltmeter said .99 to .98 all the way
>across..........guess what the afc said........... .96 to
>.95 all the way across. if you want to push your car past
>12 psi, you REALLY need to hav eyrou car tuned with multiple
>instruments (i.e. egt gauge, wideband o2 sensor, and if
>possible aftermarket knock sensor). the factory oxygen
>sensor is NOWHERE NEAR accurate enough to keep your car
>runnin if you push it. if you run mroe than 12 to 18 psi,
>you really need to be in the 11.5 to 11.3 range in air/fuel
>ratio. if you run more than 18 psi, you really need to be
>in the 11.3 to 11.0 range. if you run less than 12 psi, you
>can probably get away with running at 12.0 air fuel ratio,
>but not for long if your car isn't consistant (due to a poor
>fuel pressure regulator). if you run leaner than this, you
>"will" be buying new pistons, and if you run mroe than abotu
>21 degrees of timing at ANy of the above suggestions, your
>pistons and head and cylinder walls WILL look like someone
>went crazy with a tiny chizel around every corner and edge
>fo yoru combustion chamber and pistons. just keep timign
>around 18 to 20 degrees max under boost, and boost pressure
>under 12 psi on stock pistons and under 20 psi on
>aftermarket forged pistons on 93 octane gas, and you will be
>fine. if you don't.......you will be building another
>engine.......trust me, I know.

Relying on a rich fuel mixture alone is not good for max HP when boosting. Remember, anything richer than 10.1:1 will cause detonation also, just as easily as too lean of mixture. Then only reason is you can run soo much boost pressure without timing retard is becasuse of running on the edge of very rich conditions, thats not good for power. IMO, you will make more HP, with a slightly leaner air/fuel mixture, and retarded timing at higher HP. My EGT's never went above 1575 degrees when i was boosting 10 psi. I still cracked a piston. We HAVE to pull timing at one point or another. Its just plain physics.
Your theory of tuning is by running so rich, that it cools the intake charge enough to avoid serious detonation. The stock o2 is by far not perfectly accurate, but its pretty close overall IMO. If it wasnt, the the readings it gets would be totally inaccurate when just normal driving around, and your engine would run like crap, and get horrible gas milage. The o2 alone is what sets the Short term fuel trim, and Long term fuel trims on our cars. It HAS to be somewhat accurate at oxygen measurement. Not perfect, but close. I just wish my theories could be tested out using a dyno. Try mega rich fuel mixtures for high boost. THEN try retarding timing and leaning out fuel mixtures to where they really should be. I'd be willing to bet money that higher HP will result with leaner fuel and retarded timing. It makes sense anyway..

>oh, and also, how can the J and S safegaurd retard each
>cylinder's ignition firing when on our cars 2 cylinders fire
>at a time (waste spark). that doesn't add up to me.
>

The J&S can pull timing from each cylinder. We have 2 coils, one for cylinders 1 and 4, the other for cylinders 2 and 3. BOTH of these sets of cylinders fire at the same time, BUT only one cylinder is on the compression stroke, and the other is on the exaust stroke. So lets say cylinder 1 fires and gets detonation. The J&S reads the knock, and knows that cylinder 1 just fired, and it will remember to start to retard cylinder 1 NEXT time IT fires. So it "knows" to SKIP the next following spark trigger signal for the same coil, because now the next following signal is going to spark cylinder 4. The next spark signal after cylinder 4 is back to cylinder 1, so only then does it retard spark. Make sense? The unit listens for knock over 100 times a second.

Let me ask this also. How many of us boosted 420A guys run at 15+ psi of boost, and have actually dyno tuned our cars, using timing retard and A/F ratio adjustments? I dont know, I really cant think of many..Most 15+ psi guys just inadvertantly pull timing or run mega rich and just run it. I think we are all missing out on some good, serious HP here...Fuel tuning alone just isnt going to net max HP, we have to ignition tune also. I think we need to retard timing, and run closer to a consistant 12.1:1 to 12.5:1 A/F ratio under boosted conditions, or slightly richer, but thats it. Of course, this is all my theories anyway

13.5 @108 MPH-2.2 60ft(stupid FWD!)
S16G @ 18 PSI/FMIC/Running on MegaSquirt II (Now with sequential
fuel injection)
My webpage: http://eclipsed4evr.home.comcast.net
-1998 Mitsubishi Eclipse RS-T- "Toy"
-1992 Plymouth Laser Turbo AWD(SOLD)
-2000 Honda CR-V(daily)

Actually,

Experience has already shown us that running leaner at high levels does NOT make more power. It is very close. Accepted practice is to run in the 11.x range. Turbo cars make lots of heat. They need lots of cooling. Go ask any high hp car (single turbo Supra for example) what a/f they tune for. Also remember that load on a dyno does not equal load on the street. It will run leaner in real world conditions. Armond is not making shit up. He has been there done that. Oh, and yes, as you mentioned, the fuel is used to help cool down the engine.

I stayed quiet because I think the writeup already made on www.armond30.com explaining detonation already says enough.

Good thread.

05 Mazda RX-8
06 Lotus Elise

Hehe, yes, this is what i wanted out of this thread, good debate From what i am gathering from Armond, is that he is not using ANY timing retard up to 20 psi on pump gas??? Am I getting that right? Is this with stock 9.6:1 compression or lower compresssion? 11.0:1 is running pig rich. It does makes sense though, to run much higher boost levels to have the much needed extra fuel to help cool down the A/F charge, and lower the combustion temperature to prevent detonation. That I have no problem with, and to which i completely agree.

My point, or "theory", was instead of running such rich A/F ratios to cool the mixture and lower the temps, why not run slightly more "conservative" A/F ratios, and THEN retard timing to help cool the burn process. By retarding the time the plug fires the mixture, it helps cool down the combustion temperature be cause it makes the plug fire at a later time in the cumbustion process, later after max compression is made, therfore lower combustion temperature keeps it from detonating. Does anyone think that you are getting the maximum HP out of a 11.0:1 fuel mixture? Seems to me that there can be more power from cumbustion if the mixture contains less fuel than that, its just my idea anyway. I have another queston for Armond, as he seems to be the leader here with high HP 420A motors.. Did you use ANY form of ignition timing retard when you dyno tuned yours or any other 420A's??? I would really like some more of your input.

And as for the SAFC's, I will NEVER use one, as its cabability to add igntion timing and leaner fuel mixtures isnt what we really need with a turbosystem. For N/A applications, it can be a excellent product.

My intent of this thread was to enlighten the unknown about what our engines can and cant handle, according to spark timing. I always want to learn more, always. Knowledge is power

13.5 @108 MPH-2.2 60ft(stupid FWD!)
S16G @ 18 PSI/FMIC/Running on MegaSquirt II (Now with sequential
fuel injection)
My webpage: http://eclipsed4evr.home.comcast.net
-1998 Mitsubishi Eclipse RS-T- "Toy"
-1992 Plymouth Laser Turbo AWD(SOLD)
-2000 Honda CR-V(daily)

Xtreme,

How can you say that an SAFC isn't what we need on turbosystems? It's a very versatile instrument that is practically required to run our car's system with any increase in injector size, our computer alone can't do that well enough. Using a wideband O2 sensor and working on the dyno, guys are figuring out what A/F ratio they really need for maximum power for their particular car. With the variability in fuel and turbo systems among the 420a crew, I think using an SAFC is not only the smart thing to do, it's the safe thing to do. The SAFC is extremely useful in this because it can change the fuel mixtures and work on ignition timing itself. Ask a lot of guys with turbocharged FACTORY cars and this is one of their first mods. My 300ZX TT friends say it is a must on their cars once they are using the huge Nismo injectors. This J&S safeguard would be very useful at times, but I'm not sure the increases in power would be worth it. The safety of it on the other hand is good to have, but watching EGT and A/F ratio within your car on the gauge pod is just as important. You can't change timing yourself while your driving, yea that's great it can do that, but for those of you running your turbosystems on the street, why not just be a little conservative and run a bit rich? U aren't exactly out to destroy the competition on your way to work. Having the safeguard at the track would be nice but if you are a racer, you are prepared to break stuff and often want to have a complete stand-alone management system where you can use your laptop to change timing and fuel curves yourself. I think Armond's ideas make more sense. Also, how on earth do you figure the SAFC is useful for the NA boys? I know we have a rich spot in rpm, but what are you going to pull by leaning that out a little bit? Definitely no more than 10 hp and you'd be lucky as hell to get even that much. The NA cars are not going to make disgusting power, I would love to see an NA with no N20 make more than 200 hp and break into the 14's. Personally, I don't think it's going to happen without insane amounts of money that are definitely better spent elsewhere, i.e. turbo or different car. The more air they are moving from the intakes, headers, cams, even the porting or smoothing of head and intake manifold isn't going to allow it to make the kind of power you want, I wish it could challenge an S2000 on horsepower per liter but it's not. And with that extra air moving, the computer is going to compensate slightly and we may still run a tad rich or maybe lean depending on whether the computer picks it up or not. Regardless, you either run extra injectors, an SAFC, or a stand alone system.

Good luck with the J&S. I doubt they even make one for the car I'm building right now, Ford's EEC-IV is a great computer and we'll be running a programmer with it that let's us change timing and fuel on an rpm basis. Too bad Chrysler didn't include that kind of ability into our ECU.

Luke

1998 Mustang GT 5-speed
2002 Lone Star Shelby Cobra Replica

>Xtreme,
>
>How can you say that an SAFC isn't what we need on
>turbosystems? It's a very versatile instrument that is
>practically required to run our car's system with any
>increase in injector size, our computer alone can't do that
>well enough.

It has been proven that the SAFC WILL INCREASE timing advance. If we are running high boost, at lets say 15-18 degrees, the SAFC will automatically advance it further. Please tell me how that can be good, when we are already running on the edge of detonation?

Using a wideband O2 sensor and working on the
>dyno, guys are figuring out what A/F ratio they really need
>for maximum power for their particular car. With the
>variability in fuel and turbo systems among the 420a crew, I
>think using an SAFC is not only the smart thing to do, it's
>the safe thing to do.

Increased timing advance under boost is not good. That my friend=detonation.


The SAFC is extremely useful in this
>because it can change the fuel mixtures and work on ignition
>timing itself. Ask a lot of guys with turbocharged FACTORY
>cars and this is one of their first mods.

Yes, FACTORY turboed ecu's are much, much different than our ecu. No more explanation needed there.

My 300ZX TT
>friends say it is a must on their cars once they are using
>the huge Nismo injectors. This J&S safeguard would be very
>useful at times, but I'm not sure the increases in power
>would be worth it. The safety of it on the other hand is
>good to have, but watching EGT and A/F ratio within your car
>on the gauge pod is just as important.

I completly agree 100%

You can't change
>timing yourself while your driving, yea that's great it can
>do that, but for those of you running your turbosystems on
>the street, why not just be a little conservative and run a
>bit rich? U aren't exactly out to destroy the competition on
>your way to work.

Yes, true. But my question was how much HP *could* we gain if done with my theory. That, honestly i dont know, which is why i started this thread.

Having the safeguard at the track would be
>nice but if you are a racer, you are prepared to break stuff
>and often want to have a complete stand-alone management
>system where you can use your laptop to change timing and
>fuel curves yourself.

That would be *ideal* for a setup. At 2500+ dollars, very few can afford it. I just wanted to set out to find a more cost effective way to run higher boost, using the stock ecu. Thats all.

I think Armond's ideas make more
>sense. Also, how on earth do you figure the SAFC is useful
>for the NA boys?

I was using that as a comparison. N/A guys run rich. By leaning out the A/F ratio, and increasing timing advance somewhat, some good, reasonalbe HP could result.

I know we have a rich spot in rpm, but what
>are you going to pull by leaning that out a little bit?
>Definitely no more than 10 hp and you'd be lucky as hell to
>get even that much. The NA cars are not going to make
>disgusting power, I would love to see an NA with no N20 make
>more than 200 hp and break into the 14's.

Yeah, i would too

Personally, I
>don't think it's going to happen without insane amounts of
>money that are definitely better spent elsewhere, i.e. turbo
>or different car. The more air they are moving from the
>intakes, headers, cams, even the porting or smoothing of
>head and intake manifold isn't going to allow it to make the
>kind of power you want, I wish it could challenge an S2000
>on horsepower per liter but it's not. And with that extra
>air moving, the computer is going to compensate slightly and
>we may still run a tad rich or maybe lean depending on
>whether the computer picks it up or not. Regardless, you
>either run extra injectors, an SAFC, or a stand alone
>system.
>
>Good luck with the J&S. I doubt they even make one for the
>car I'm building right now, Ford's EEC-IV is a great
>computer and we'll be running a programmer with it that
>let's us change timing and fuel on an rpm basis. Too bad
>Chrysler didn't include that kind of ability into our ECU.

Yep, ditto on that. I am just out to find the best, most costeffective way to build High HP on our cars, without spening mad amounts of money. I think there is a different(not necc the best), alternative to do it. Timing retard, and more conservative A/F ratios is my theory. Its just that, until i prove it otherwise. I'm in no way saying this is the one, single most answer to the question of tuning. It was an idea that was sparked from my detonation experience. I always like to look at things from a different point of view. I like to contest current theories and "facts" to provoke thought, and better ideas. Where would the science and technological world be without people like that?? Future dyno sessions on my car will be taking place in the spring time for sure. I will try both known methods of tuning. I am curious to see the results. I need to prove it to myself. We will see what happens. Maybe i can work something out with J&S for testing of their product. If i blow the engine, its ok, i have the skills to rebuild it. Whats a little money anyway?

13.5 @108 MPH-2.2 60ft(stupid FWD!)
S16G @ 18 PSI/FMIC/Running on MegaSquirt II (Now with sequential
fuel injection)
My webpage: http://eclipsed4evr.home.comcast.net
-1998 Mitsubishi Eclipse RS-T- "Toy"
-1992 Plymouth Laser Turbo AWD(SOLD)
-2000 Honda CR-V(daily)

>Xtreme,
>
>How can you say that an SAFC isn't what we need on
>turbosystems? It's a very versatile instrument that is
>practically required to run our car's system with any
>increase in injector size, our computer alone can't do that
>well enough.


actually, it can. if you control the fuel pressure properly, you can get "very" close in the ball park with extremely large injectors. I think xtreme is trying to say that relyin on an afc on a 1 bar map sensor equiped car adds it's share of problems with every advantage. sure you can reduce injector pulse with, but when you do, the ecu senses less load, and increases timing accordingly, sometimes as high as 30 degrees advance at WIDE OPEN THROTTLE. that is too much ignition timing for "any" turbocharged car. then with the afc, you have to buy something to piggyback on the ecu to correct the timing issue. it just turns into another problem after a while instead of a solution. if it is used to "fine tune", it is a very good tool (i.e. no more than 10 % in either direction).

I
>think using an SAFC is not only the smart thing to do, it's
>the safe thing to do.

it is only safe if it is used knowing 'all the other parameters' involved in the corrections. if it is used blindly, it can be "quite destructive"

My 300ZX TT
>friends say it is a must on their cars once they are using
>the huge Nismo injectors.

I agree. on factory turbocharged cars, the AFC can be a fery useful tool I use one on my dodge stealth, and it runs 12.60's with the help of the afc and larger injectors. the 300ZX uses a mass air-flow sensor which is "not" normally maxed out at wide open throttle. leaning out a car wiht some type of mass air flow meter is relatively harmless, and does not cause as many headaches as 1 bar map sensor cars (like our cars, or hondas, etc.). leaning out systems like this will also increase ignition timing advance, but on the same sence, these vehicles usu. don't need much adjustment with large injectors, as the factory injectors are usu. fairly decently sized from the factory. Guess what people do to control the extra timing 'though...............dump more fuel . that's how Dynamic racing ran a 10.8 with thier dodge stealth. mas air flow sensor conversion and correction with 720 cc injectors...........at lower boost, there is QUITE a good deal too much timing, but running 10.80's makes teh timing just right. usu. people that hav elarger injectors run higher boost which flows more air wich brings the "corrected" air-flow count closer to what it would be from the factory at wot on a boosted car. most of those guys also usu. don't go around boosting low either and if they do, they hav eenough fuel at partial throttle to handle it......or they buy new pistons as well. that's the way it works with my stealth


Also, how on earth do you figure the SAFC is useful
>for the NA boys? I know we have a rich spot in rpm, but what
>are you going to pull by leaning that out a little bit?
>Definitely no more than 10 hp and you'd be lucky as hell to
>get even that much. The NA cars are not going to make
>disgusting power, I would love to see an NA with no N20 make
>more than 200 hp and break into the 14's.

well, to each their own. some guys go balistic over 5 hp gains. true, a s-afc won't make 30 hp difference on a n/a eclipse, but it will make relatively the same percentage of gain hp wise as it would on a turbocharged car. it's just the power comes in a smaller package



A.D.P.
"...If you do too much, people become dependant. If you do to little, people loose hope. If you do it right, people won't be sure you've done anything at all."
bring it on............

A.D.P.
"...If you do too much, people become dependant. If you do to little, people loose hope. If you do it right, people won't be sure you've done anything at all."
bring it on...........

> By retarding the time
>the plug fires the mixture, it helps cool down the
>combustion temperature be cause it makes the plug fire at a
>later time in the cumbustion process, later after max
>compression is made, therfore lower combustion temperature
>keeps it from detonating.


you will have a "less chance of detonation' if yo udo that, but you hav eto rememerb, I dont' run a vc-1,vc-2, mising link, or anything like that, and I had the stock ecu from murix's car in my car for quite a while. under boost, I was getting about 15 degrees of spark advance. if I wa sto retard timing 5+ degrees more than that, the car woudl make "no power" (tried it on the dyno.......it was pathetic. can you say 305 hp on MY car with all the flow work, all the cams, everything, etc. with 18 psi). plus my egt's with 12.3"1 air/fuel ratio were through the roof (I was getting 1650 out of the center 2 cylinders on the dyno!............which come to find out is too hot fo ran engine. got the piston to prove it.) retarding timing does not cool combustion temperature. it reduces the chance fo it being soaked into the motor. insted all that head goes out the exhaust valves and through the valve stem seals. watch yoru egt's close when you retard timing. they will go up with NO changes except reduced timing. that is why. it maybe safer for the motor as a whole, but it reaks havoc on the valves. I know a supra guy back in the day that retarded timing by a whim and tuened a few of his exhaust valves into butter (he was getting about 16 degrees base timing also)! if you tune fo ra higher air fuel ratio, you will have a much more radical ignition of the fuel, which will increase heat and force, but retardign the timing will push much of the heat and potential force through the exhaust and turbo, resulting in extreme spoolups, and holes in pistons. if you run richer, you can have a much mroe controllable burn, and use more of the energy from the combustion to produce torque, and still have enough exhaust heat left over for good turbocharger effiency (assuming a low amount of convetion through the exhaust manifold and turbine housing).


Does anyone think that you are
>getting the maximum HP out of a 11.0:1 fuel mixture? Seems
>to me that there can be more power from cumbustion if the
>mixture contains less fuel than that, its just my idea
>anyway. I have another queston for Armond, as he seems to be
>the leader here with high HP 420A motors.. Did you use ANY
>form of ignition timing retard when you dyno tuned yours or
>any other 420A's??? I would really like some more of your
>input.

when we tuned mark's car (96 venger) we used 0 timign retard due to the fact that his car was making a consistant 18 degrees of timing to begin with. his car also did not rattle on the dyno, and it produced a save ammount of hp consistantly. The manual boost controller that is on the car (turbo xs) is really flaky, so no more than 12 psi was ran on the dyno. the turbo woudl overshoot about 4 psi with this boost controller, and even at the 16 psi spike , the car held rock solid and made consistant hp, and did not rattle. we raised the car all the way to a consistent 15 psi (which resulted in a 19.5 psi spike and the car made a save, noise free 270 hp "after" the spike with an air/fuel ratio of 11.3:1 and considerably low exhaust gas temperatures. no one at the dyno felt that it was safe to push the car with a "consistant" 20 psi spike on 93 octane with an "average" of 18 degrees advance, even at 11.3:1 air/fuel ratio, so the boost wa sbrought back to 12 psi. as far as I know, the car still runs pretty rock solid, and still has perfect compression. it makes around 240 hp at 12 psi on average, but ignition timing "can be flaky" with these cars, and can increase or decrease on a whim. the car ahs made as much as 260 hp at the same boost level randomly (no doubt due to ignition timing. he runs the missing link. that is the "MAIN" reason to keep an eye on timing.....glitches. MuRix's car hasn't been dyno tested in years, but it ha sbeen "almost there" countless times. his car however has performed well with 0 retard at 18 psi with little aftermarket help. no visible damage to the spark plugs, and no abnormal changes in compression. ran like hell to say the least. I hav eanother friend that frequents here that ran 12 psi on stock pistons for about 2 years with an aftermarket head gasket with NO timing retard. no afc either. just a standard HRC stage 2 turbosystem, cams, and a thick head gasket. his car was strong as hell also. as soon as the afc went on and the car was leaned out 30% across the board..........dents in the pistons formed, putting the motor out of commission a few times. I had no part in tuning this car, but it is blatantly obvious now that those issues were caused by "abnormal timing". the car was even relatively rich (once again by his oxygen sensor), and the motor still failed.......a few times. you can't run rich and run "all the timing you want". that's not what I am saying. you have to run the "right" ammount of timing, and you have the combustion temperatures in a "safe range" at the same time. too much timing will enlarge existing problems. too little fuel will create more heat than a normal motor can stand at 220 psi of compression pressure. the higher the compression pressure, the more extreme the danger. if you run over 12:1 air fuel ratio when yoru turbo is in it's island effiency or higher, you will fill the cylinders with enough explosive to cause uncontrolable damage. at lower pressures, the density and speed fo the air is thick and slow enough to only use small ammounts of fuel, therefore resulting in lower ammounts of force overall. the mroe more air you blow in, the mroe fuel it takes, and the more potential there will be for force........until you cross that barrier where the ammount of air requires enough fuel to either work the motor, or "work the motor over" if you know what I mean, and if "that much fuel" isn't burned properly, you are bound for dammage. with the 20G, that point is about 15 psi. running leaner than 11.5:1 at lower boost levels is really just "getting away with it". with the same ammount of air flow on a smaller motor, that would result in more boost, and would hav ethe same result as running the increased airflow on the larger motor (in this case ours). of course this is all in laymans terms, but trust me. after going through 4 engines, you tend to learn a few things. not sayin I know everything, but I know what "lean" is now.

A.D.P.
"...If you do too much, people become dependant. If you do to little, people loose hope. If you do it right, people won't be sure you've done anything at all."
bring it on............

A.D.P.
"...If you do too much, people become dependant. If you do to little, people loose hope. If you do it right, people won't be sure you've done anything at all."
bring it on...........

>
>Relying on a rich fuel mixture alone is not good for max HP
>when boosting. Remember, anything richer than 10.1:1 will
>cause detonation also, just as easily as too lean of
>mixture. Then only reason is you can run soo much boost
>pressure without timing retard is becasuse of running on the
>edge of very rich conditions, thats not good for power. IMO,
>you will make more HP, with a slightly leaner air/fuel
>mixture, and retarded timing at higher HP. My EGT's never
>went above 1575 degrees when i was boosting 10 psi. I still
>cracked a piston. We HAVE to pull timing at one point or
>another. Its just plain physics.


not really. if you are getting 15 degrees of advance (like I do with a stock ecu, and no map sensor correction) adn you take out 8 degrees of timing to run over 15 psi.......you are running SEVEN DEGREES OF ADVANCE. that doesn't work. you will MELT valves doing that. you have to know what your timing looks like to begin with and not jsut blindly retard timing when you think it's good to. running leaner than 11.3 to 11.5:1 even with 16 degrees of timing advance on a "well flowing motor" will melt stuff. I had my car tuned PERFECTLY to 12.2:1 at wot on the dyno, and my egt's never went above 1550 either........after I put in the afx ecu and didn't remember to correct for it. (remember the 10 extra degrees of timing). I put a hole in a piston the size of a human thumb. when you get over the hump and start soaking heat into your pistons and head and cylinder walls, egt's go "down". more heat is transfered through the metal, and less is transfered thorugh the exhaust. tuning for Max hp is "not" what you want to do for longevity of yoru engine. it is great for drag racing when extra engines are available, but if you do tune fo rmax hp, you will burn stuff, bust stuff, and utterly break things constantly (I was tuning for max hp when I tweaked the car for 12.2:1 air fuel ratio). if tuned properly, you can make almost as much hp as peak consistantly and safely with the right ammount of fuel and the correct ammount of spark advance. most single turbo supras tune for about 11.3 to one on teh dyno and 11.8:1 on the street (what the load generally caries the number up to) and abotu 16 degrees of spark advance to run 20 psi on pump gas........they most of those guys have NEVER removed an engine due to damage (I talk with a lot of them, because most of the local guys around here have their act together).


>Your theory of tuning is by running so rich, that it cools
>the intake charge enough to avoid serious detonation. The
>stock o2 is by far not perfectly accurate, but its pretty
>close overall IMO. If it wasnt, the the readings it gets
>would be totally inaccurate when just normal driving around,
>and your engine would run like crap, and get horrible gas
>milage. The o2 alone is what sets the Short term fuel trim,
>and Long term fuel trims on our cars. It HAS to be somewhat
>accurate at oxygen measurement. Not perfect, but close.


the oxygen sensor is pretty stable and consistant "if it stays at a relatively consistent hot temperature". if you run without a cat, or run open exhaust, etc. etc. etc. really rich mixtures can cool the exhaust so much that the 02 sensor becomes inaccurate. this usu. happens at wot runs with a cool car. this is usu. the time when something will mess up. I have acutally seen cars run so cool that once ran as soon as the o2 sensor reached operational temps, the exhaust knocked it back in warm-up mode (even wide band sensors). on a relatively stock car, that is pretty much in tune from the factory, the o2 sensor has to do very little. on a heavily modified car, the o2 sensor has to usu. adjust much more, and that's where you start to find inconsistencies. I have seen my o2 sensor in my stealth read .98 on the dyno and .95 on the dyno and have the "exact same air/fuel ratio" via a wideband sensor and a logged graph. it is possible to have glitches, and less backpressure in the exhaust (lack of cat) increases that risk.



I just wish my theories could be tested out using a dyno. Try
>mega rich fuel mixtures for high boost. THEN try retarding
>timing and leaning out fuel mixtures to where they really
>should be. I'd be willing to bet money that higher HP will
>result with leaner fuel and retarded timing. It makes sense
>anyway..

I have. retarding timing decreases hp output from my car. (with the accell dfi and no pressrue sensor clamp, my wot timing is abotu 19 degrees). leaning the car out also increases power. that is very blatant on the dyno. it also makes it rattle 'slightly' on the dyno, and rattle "extremely" on the street.......causing holes in pistons (personal expierence)


>The J&S can pull timing from each cylinder. We have 2 coils,
>one for cylinders 1 and 4, the other for cylinders 2 and 3.
>BOTH of these sets of cylinders fire at the same time, BUT
>only one cylinder is on the compression stroke, and the
>other is on the exaust stroke. So lets say cylinder 1 fires
>and gets detonation. The J&S reads the knock, and knows that
>cylinder 1 just fired, and it will remember to start to
>retard cylinder 1 NEXT time IT fires. So it "knows" to SKIP
>the next following spark trigger signal for the same coil,
>because now the next following signal is going to spark
>cylinder 4. The next spark signal after cylinder 4 is back
>to cylinder 1, so only then does it retard spark. Make
>sense? The unit listens for knock over 100 times a second.


that is pretty smart .


>
>Let me ask this also. How many of us boosted 420A guys run
>at 15+ psi of boost, and have actually dyno tuned our cars,
>using timing retard and A/F ratio adjustments? I think we need to retard
>timing, and run closer to a consistant 12.1:1 to 12.5:1 A/F
>ratio under boosted conditions, or slightly richer, but
>thats it. Of course, this is all my theories anyway


I think people not going to the dyno is the main cause of engine failure from this board. but it isn't going to be solved running 12.5:1 air/fuel ratio and 2 degrees of timign advance. I think everyone should learn how to do things, but I just feel bad knowin for a fact that something bad is goin to happen. if you run 12.5:1 air fuel ratio past 15 psi, you "absolutely will" burn something half to death. if you don't retard timing, you will melt your pistons (aftermarket) or crack ring lands (cast pistons) and if you retard timing at that air/fuel ratio, you will melt your exhaust valves and burn up your valve stem seals. been there. done that. got about 7 dead pistons of experience.

A.D.P.
"...If you do too much, people become dependant. If you do to little, people loose hope. If you do it right, people won't be sure you've done anything at all."
bring it on............

A.D.P.
"...If you do too much, people become dependant. If you do to little, people loose hope. If you do it right, people won't be sure you've done anything at all."
bring it on...........

Armond, thank you for your thoughts. It makes much more sense now. Its what I intended out of this thread, really. This brings me to another question, though. From what you are saying, we cant have the best of both worlds, right? I plan on rebuilding with 8.5:1 pistons. I plan on at first, running 10 psi, then going up to 15 psi. What do you think will be the best setup for this? You are saying to run around 11.0 - 11.3 or so A/F ratio, at WOT boost? With NO spark retard, just running the stock ecu WOT timing curve? Is that right? How high of boost can I go with the 8.5 compression, without using any spark retard, or before detonation sets in? I'm very curious.. I as are many others are going this setup, or may already have their motors set up with this or close compression ratio. At what point do you think we *need* to retard timing? From what I thihk you are saying, we need to add more fuel, increasing the actual A/F ratio, as boost pressure increases, INSTEAD of retarding timing? If thats the case, then all of the literature i have read up on, ect..is wrong? All of what i have read says with increased cylinder pressure, you need to retard timing, AND add the fuel of course..

What do you think of this. They talk of a n2o setup, but its still forced induction:

"Understand that, in our quest to delay cylinder pressure’s peak time, more is not necessarily better. Instead, consider that the ideal cylinder pressure would be just short of detonation pressure and this pressure would be maintained from top dead center, and as long as possible after TDC. If timing is really late, you won’t build enough cylinder pressure to start the car, let alone drive it. The 1000 PSI pressure in the example is not the maximum allowable combustion pressure but, rather, a comfortable pressure for illustration of the work principle.

Some nitrous manufacturers recommend, "retard the timing two degrees for each fifty horse power of nitrous". Other nitrous kits have the flame speed artificially slowed by the intentional use of a rich fuel to nitrous ratio. The maximum performance engine with a heavy nitrous load must achieve peak cylinder pressure progressively further after TDC. The heavy load engine will have the fuel and oxygen mix to make high cylinder pressures, with the combustion chamber size being drastically increased due to the piston being on its way toward bottom dead center. The strongest engines have less compression ratio, less spark advance, and more nitrous.

I have tried to explain the reason for a spark retard system in a Nitrous engine. However, many people just don’t like the idea of any retard. They say, "retard timing and exhaust heat goes up". It usually does in a stock nonnitrous engine because lower peak cylinder pressure slows the burning. If the timing is retarded in a non-nitrous engine, the exhaust opens before the fuel mix is finished burning and exhaust temperatures go up. Piston temperatures usually go down and exhaust valve temperature goes up. In the nitrous engine, exhaust temperature goes up for several reasons. The first is that the power output has gone up considerably. More power usually produces more waste heat. Second, the need to keep maximum cylinder pressures within reason has dictated that the biggest part of the fire happens closer to the exhaust valve opening time. There just isn’t enough piston travel to extract all the energy out of the charge before the exhaust valve opens. Now, we could and sometimes do, open the exhaust valve later so more combustion pressure energy can be used to turn the crank. The trade off is negative torque on the exhaust stroke. If we still have significant cylinder pressure in the cylinder as the piston moves from BDC to TDC on the exhaust stroke, your net Hp falls drastically. A real problem at higher RPM."

This is the link to all of it: http://www.kb-silvolite.com/page14.htm

13.5 @108 MPH-2.2 60ft(stupid FWD!)
S16G @ 18 PSI/FMIC/Running on MegaSquirt II (Now with sequential
fuel injection)
My webpage: http://eclipsed4evr.home.comcast.net
-1998 Mitsubishi Eclipse RS-T- "Toy"
-1992 Plymouth Laser Turbo AWD(SOLD)
-2000 Honda CR-V(daily)

>Armond, thank you for your thoughts. It makes much more
>sense now. Its what I intended out of this thread, really.
>This brings me to another question, though. From what you
>are saying, we cant have the best of both worlds, right? I
>plan on rebuilding with 8.5:1 pistons. I plan on at first,
>running 10 psi, then going up to 15 psi. What do you think
>will be the best setup for this? You are saying to run
>around 11.0 - 11.3 or so A/F ratio, at WOT boost? With NO
>spark retard, just running the stock ecu WOT timing curve?
>Is that right? How high of boost can I go with the 8.5
>compression, without using any spark retard, or before
>detonation sets in? I'm very curious.. I as are many others
>are going this setup, or may already have their motors set
>up with this or close compression ratio. At what point do
>you think we *need* to retard timing? From what I thihk you
>are saying, we need to add more fuel, increasing the actual
>A/F ratio, as boost pressure increases, INSTEAD of retarding
>timing? If thats the case, then all of the literature i have
>read up on, ect..is wrong? All of what i have read says with
>increased cylinder pressure, you need to retard timing, AND
>add the fuel of course..



hmm. that is a pretty full question. (me like ). you can not have the best of all worlds (when you are looking for power, there is more than just timing and boost). fuel grade, exhaust temperature, and intake temperature all are equally important on a turbocharged car. the type of turbocharger is really essential in figuring out maximum boost capable of achieving safely. if all you intend on running is 15 psi, a super 16g turbo with a short manifold (like the hrc setup) will do the job nicely and smoothly. the 16g has a lot of the same characteristics as my 20G, including the same turbine housing. wiht this turbo, you will start to notice "stuff happen" at around 15 psi. that is when the egt's jump up for no apperant reason at the same air/fuel ratio. if you run a missing link orvc-2 or whatever, keep a close eye on yoru ignition timing. at 10 psi, you can get away with 12.3 or so air/fuel ratio on the dyno (12.7 or so on the street max), and the car will be more efficient, but around the 15 psi range, the air/fuel ratio needs to decrease with the increase in egt's (which usu. puts it around 11.5 on the dyno, and 12.0 on the street. going slightly higher to around 20 to 21 brings you past the hump in the effiency curve and that's where your air/fuel ratio needs to stabalize around 11.1 on the dyno. everything beyond that is usu. ok at that air/fuel ratio, depending on yoru fuel grade. that becomes the main variable in extreme cylinder pressure conditions (meaning no matter what air/fuel ratio you go to, the fuel is going to burn too violently irregardless........unless you go with a thicker fuel . that happens when you get out of the linear range where fuel burns (between 10.5 to 17.0 air/fuel ratio). in a nutshell, what I am trying to say is when your turbo gets to work, and starts increasing engine load by a "good deal" (when you start getting exhaust backpressure, and heat starts seeping out of stuff). you richen up the car until you get to that point where fuel won't burn, then you have to go to another level of fuel, in which case, you start out adjustments at a higher point again because the extra control gtiven by the octane count can be counteracted by the intensity of the burn via the air/fuel ratio. (this is confusing even sayin it, so I will giv ea different comparison.....I wish I could use a graph). say you get into your engine/turbocharger's peak effiency range (where your car starts makign stupid power and starts makign wierd noises usually). for my car, that is between 15 and 21 psi with the wastegate open. below this point, on 93 octane gas, air/fuel ratio can be around 12.3 to 1 (minimum)on the dyno with no problems due to lack of load (less force). above this range, 93 octane gas can't be controlled well enough to give a safe consistent burn. in between this range there is a slope of safety, which extends higher in the lower range (that's why some all motor cars can run 14.5:1 on a daily basis and now blow up. this is all assuming constant ignition timing (in this case 18 degrees advance. at around 21 psi, you would have to run at about 11.5 to 11.3:1 in my car at that ignigion timing to keep the burn strength down in a controllable range (below 1550 degrees) on the street. on the dyno, the car must be tuned for even lower air/fuel ratio due to lack of load from drag (that is why I always blew my engine going around 130 mph). sure, you could run higher boost on the street if you tuned for even lower air/fuel ratio, but that is "very close to being either "hit or miss" as far as attomization goes at those cylinder pressures (which causes pre-ignition, and/or incompressibility of the fuel). when you go to a higher octane fuel, it burns slower, so less thermal energy is released (i.e. lower egt's.....which is usu. deemed becasue the engine isn't working as hard......that's wrong). with this more controlled fuel, you can run even higher air/fuel ratios to bring the combustion "violence" up to par, without havign to worry about overloading the cylinders with liquid. that is why you have to run high octane gas to run higher boost safely. this is also why I tune for 11.3:1 at 30 psi with 116 octane fuel. it has been proven that my ca rca rrun "drastically leaner" than that on high octane fuel, but dammage happens a LOT faster and a LOT les forgiveing at higher boost levels than at lower boost levels. (that is a mouthfull, but I hope that explains the entire air/fuel ratio curve deal). with 18 degrees of timing advance (stock with a missing link on a boosted 420A) you should be safe runnning 11.5:1 on the dyno at 15 psi. the street will increase load according to speed. if you run 130 mph plus on a regular basis, I would reccomend tuning a little richer than this. mayb 11.3 maximum on teh dyno). having a wideband o2 sensor in the car is even better, that way you can see exactly what is happening, and when your air/fuel ratio is increasing due to increased load on the motor. if you tune for 11.3 to 11.1:1 air fuel ratio on the dyno, at 18 psi, you should be able to run 93 octane gas safely without timing retard (granted your ignition timing stays at a max of 18 degrees). this will put you at about 11.7 to 11.5 on the street. that is pushing it for pump gas on a decently efficient 4 cyl car. I reccomend running a slight mix of high test gas if you can for 18 psi (I don't kno why I dont' take my own advice.......probably becasue I don't mind fixing my own car as much as I mind fixing others). over that, I would "really consider running "pure" 100 octane fuel for stock ignition timing. you can run a mixture of half and half after 18 psi........IF you retard the timing 3 or so degrees (keeping the car at around 11.1:1 air/fuel ratio on the dyno, and 11.5 on the street). the extra thick fuel will keep temperatures moderately down, and the retarded timing will reduce the extra force put on the entire system. retarding timing below 15 degrees advance is "iffy" and should never be necessary if the correct grade and correct ammount of fuel is used on any application. once you start doign that , you start transfering combustion energy from makign the piston go up and down, to making the turbocharger spin (which is good in some cases....i.e. if you need spool IMMEDIATELY like during a rally race), but it also transfers the dammage. 1600+degree heat will break "something" saying you have to retard timing under boost is a generic tip, like saying you have to have a blow off valve if you run over 6 psi. there is more to it that is really in-depth that most people skip over. I hope I explained it well enough.



this next one is kinda long. I will try to break it apart in steps.


>>
>"Understand that, in our quest to delay cylinder pressure’s
>peak time, more is not necessarily better. Instead, consider
>that the ideal cylinder pressure would be just short of
>detonation pressure


not true. detonation pressure is usu. EXTREMELY higher than the engine bearings and cylinder components can handle. this is why detonation hamers out rod bearings, whereas normal compression......even high hp compression doesn't.

and this pressure would be maintained
>from top dead center, and as long as possible after TDC. If
>timing is really late, you won’t build enough cylinder
>pressure to start the car, let alone drive it. The 1000 PSI
>pressure in the example is not the maximum allowable
>combustion pressure but, rather, a comfortable pressure for
>illustration of the work principle.
>
>Some nitrous manufacturers recommend, "retard the timing two
>degrees for each fifty horse power of nitrous". Other
>nitrous kits have the flame speed artificially slowed by the
>intentional use of a rich fuel to nitrous ratio. The maximum
>performance engine with a heavy nitrous load must achieve
>peak cylinder pressure progressively further after TDC. The
>heavy load engine will have the fuel and oxygen mix to make
>high cylinder pressures, with the combustion chamber size
>being drastically increased due to the piston being on its
>way toward bottom dead center. The strongest engines have
>less compression ratio, less spark advance, and more
>nitrous.

also not true.........the most reliable engines have less compression, lower spark advance, and more nitrous. the more timing advance you add, the more power you will gain, on anything (not saying that it will hold together, but it will make more power without question). same thing with compression. gary howell hit on compression and boost before amd made several good points about that.


>
>I have tried to explain the reason for a spark retard system
>in a Nitrous engine. However, many people just don’t like
>the idea of any retard. They say, "retard timing and exhaust
>heat goes up". It usually does in a stock nonnitrous engine
>because lower peak cylinder pressure slows the burning. If
>the timing is retarded in a non-nitrous engine, the exhaust
>opens before the fuel mix is finished burning and exhaust
>temperatures go up. Piston temperatures usually go down and
>exhaust valve temperature goes up.

exactly correct

In the nitrous engine,
>exhaust temperature goes up for several reasons. The first
>is that the power output has gone up considerably. More
>power usually produces more waste heat. Second, the need to
>keep maximum cylinder pressures within reason has dictated
>that the biggest part of the fire happens closer to the
>exhaust valve opening time. There just isn’t enough piston
>travel to extract all the energy out of the charge before
>the exhaust valve opens.


this happens anytime power generated is increased drastically (i.e. turbocharger entering it's peak efficiency range). Now, we could and sometimes do,
>open the exhaust valve later so more combustion pressure
>energy can be used to turn the crank. The trade off is
>negative torque on the exhaust stroke. If we still have
>significant cylinder pressure in the cylinder as the piston
>moves from BDC to TDC on the exhaust stroke, your net Hp
>falls drastically. A real problem at higher RPM."

I want to hear more




>
>This is the link to all of it:
>http://www.kb-silvolite.com/page14.htm

A.D.P.
"...If you do too much, people become dependant. If you do to little, people loose hope. If you do it right, people won't be sure you've done anything at all."
bring it on............

A.D.P.
"...If you do too much, people become dependant. If you do to little, people loose hope. If you do it right, people won't be sure you've done anything at all."
bring it on...........

Armond, thanks for taking the time to type all that out It now makes sense of what you are saying, and how we should tune. I hope many others on the forum will read this, and take it all in, understanding it. This was wayyyy more complicated than anticipated, just so many variables to consider when actually tuning on an individual car/ turbo basis. As said in one of your replies, I agree 100% that more of us NEED to dyno tune our turbosystems when we run higher amounts of boost pressure. I def plan on doing this in the following months of downtime. Wow, look at the hits on this thread. Finally, some real good, thought provoking discussion here

This now brings me back to my other thoughts in my earilier post. What do you think about the closed loop, part throttle boost situation? If we can part throttle boost in closed loop, timing can be advanced upwards of 30 degrees, and the ecu is trying to control the A/F ratio close to the "normal" 14.7:1 ratio. We cant run more fuel in this type of situation, as the ecu is controlling the ratio. Should we be concerned with this? How do you think we should go about this? I would think running 10psi in closed loop, with 30 degrees of timing will most def cause detonation. As far as daily drivability is concerned, i know i part throttle, close loop boost all the time, not WOT boost. What do you think?

13.5 @108 MPH-2.2 60ft(stupid FWD!)
S16G @ 18 PSI/FMIC/Running on MegaSquirt II (Now with sequential
fuel injection)
My webpage: http://eclipsed4evr.home.comcast.net
-1998 Mitsubishi Eclipse RS-T- "Toy"
-1992 Plymouth Laser Turbo AWD(SOLD)
-2000 Honda CR-V(daily)

yeah, 10 psi and 30 degrees of timing is bad . but, on the positive side, at partial throttle, you aren't putting the engine under as much load as maximum, even though boost pressure is being made in the manifold. usu. when you hit max pressure on the map sensor, the timing should fall back down to around 20 degrees. hmm.....if the ignition timing isn't falling to safe levels at partial throttle boost, then there is a problem .......I have only checked my timing under these conditions a few times, and I am not 100% positive that ignition timing falls during this condition. if it does, no worries. if it doesn't.........ewuuu. realistically, timing should drop as soon as you hit boost. on my car, at partial throttle boost, my car never really "rattled" like it woudl if it had that much timing. I woudl look "really close" at the dattalogger (this goes to anybody that has a logger and a turbo, as my car is kinda disqualified from this for the next couple of weeks ). and see what the timing is. with such a big turbine housing as the super series turbos have, the timing should drop from boost pressure and throttle position under partial throttle boost. if it doesn't........I honestly don't know hwo to get around it unless you run some kind of timing retard device that would de-activate at 100% throttle and activate at 0 psi. I think that you will be ok 'though. best thing to do it check and tell us the results of partial throttle boost via spark advance on the datalogger, egt and guestamite air/fuel ratio if possible.

A.D.P.
"...If you do too much, people become dependant. If you do to little, people loose hope. If you do it right, people won't be sure you've done anything at all."
bring it on............

A.D.P.
"...If you do too much, people become dependant. If you do to little, people loose hope. If you do it right, people won't be sure you've done anything at all."
bring it on...........

Damn I've got a headache...

with just a SAFC to adjust fuel, and if your boost plans are "moderate", has anyone considered NOT using such huge injectors(like 440's) that are kinda overkill for those boost levels? that way you rely LESS on the SAFC( you lean it less) and timing isnt messed with it as much as a result. if i did it over again, id run 12psi daily, and 15psi at the track on race gas, with, say 30lb injectors. you wouldnt be leaning the high throttle settings by more than 15%( i wouldnt think), and timing shouldnt be affected too badly. some might not wanna run "high" fuel pressures, like over 100, but it doesnt bother me too much. crisp throttle response is appreciated, and thats what they make stainless braided fuel line for...

1997 Silver RS
Built
T3/T4 BB Turbo
20psi
Most current 1/8th mile time: 8.1@93mph 2.015 60'
1996 Black Supra TT
2004 Silver Snake

Someone explain how you calculate your a/f ratio, like 11.3:1 etc, etc, etc.

TIA
Brian

Armond, or someone, i use to use the hrc and vc-2 set at 4.5-4.7v once into boost, but recently i got the 'missing link' which i understand is not good since timing can vary? depending on temp, load, elevation etc?... please correct me if im wrong? each time i look at my map sensor voltage i get 4.5-4.56v with the 'missing link' under boosted operation in so cal .
should i rather use the vc2 "voltage clamp" set at 4.7 instead of this missing link? so it will hold timing 'better' or will it be the same?
thanks


Michael 99gs
HRC Stage 2
Stage 3 process begins anyone got a 420a block thats not spun/head for sale?

http://www.dreamwater.net/purplebeast

Michael
99gs hrc stage 5000 SOLD...
2004 Honda Accord V6 (240 hp)stock
what other car should i buy?? hmmm
Car info & pictures at http://www.cardomain.com/memberpage/520269

I did not say the missing link was nto a good part. several things can affect ignition timing. you just have to make sure you are in a safe enough area so tht aif your timing does randomly jump up 3 or so degrees, you don't get detonation because of it. running a vc-2 will cause a map sensor error code.......which will make you fail emmissions inspection in metro atlanta, so I don't reccomend them. I think that fuel cut is based mroe on injector pulse width than anything.

A.D.P.
"...If you do too much, people become dependant. If you do to little, people loose hope. If you do it right, people won't be sure you've done anything at all."
bring it on............

A.D.P.
"...If you do too much, people become dependant. If you do to little, people loose hope. If you do it right, people won't be sure you've done anything at all."
bring it on...........

the main problem with that is that I have already proven that you don't have to lean your car out extreme ammounts with an afc and 440 cc injectors. heck. Murix's car ran 525's with a 1:1 regulator. with a vortech S-fmu, you can almost get the air/fuel ratio pretty much perfect, and not affect driveablilty. it just takes a bit of tuning to do (and that doesn't even take that long). if you go with smaller injectors, you will just be limited in the future (just like people that buy small turbos for built cars)

A.D.P.
"...If you do too much, people become dependant. If you do to little, people loose hope. If you do it right, people won't be sure you've done anything at all."
bring it on............

A.D.P.
"...If you do too much, people become dependant. If you do to little, people loose hope. If you do it right, people won't be sure you've done anything at all."
bring it on...........

>yeah, 10 psi and 30 degrees of timing is bad . but, on
>the positive side, at partial throttle, you aren't putting
>the engine under as much load as maximum, even though boost
>pressure is being made in the manifold. usu. when you hit
>max pressure on the map sensor, the timing should fall back
>down to around 20 degrees.

So is the switch between open and closed loop based on MAP? I thought it was on throttle position. I thought that 80% throttle put you into open loop and everything below it throws you into closed loop. Can someone please clear this point up?

>hmm.....if the ignition timing
>isn't falling to safe levels at partial throttle boost, then
>there is a problem .......I have only checked my timing
>under these conditions a few times, and I am not 100%
>positive that ignition timing falls during this condition.
>if it does, no worries. if it doesn't.........ewuuu.
>realistically, timing should drop as soon as you hit boost.
>on my car, at partial throttle boost, my car never really
>"rattled" like it woudl if it had that much timing. I woudl
>look "really close" at the dattalogger (this goes to anybody
>that has a logger and a turbo, as my car is kinda
>disqualified from this for the next couple of weeks ).
>and see what the timing is.

I wish i had a datalogger....and a turbo.

>with such a big turbine housing
>as the super series turbos have, the timing should drop from
>boost pressure and throttle position under partial throttle
>boost. if it doesn't........I honestly don't know hwo to
>get around it unless you run some kind of timing retard
>device that would de-activate at 100% throttle and activate
>at 0 psi.

Kind of like the loop controller I was talking about.

>I think that you will be ok 'though. best thing
>to do it check and tell us the results of partial throttle
>boost via spark advance on the datalogger, egt and
>guestamite air/fuel ratio if possible.

Can someone do this for this thread. It looks like neither Armond or I can. At the very least, can someone please clarify what-it-is that dictates the loop state(open or closed) on our ECU?


ride__________95 Eclipse RS : 5 speed
power________Gude cams : AFX UDP : ram air : test pipe : GST catback
suspention___BOMZ F/R upper strut bars : ES inserts
sound________Kenwood KDC 5000 : Audiovox 8" sub toob - no sub amp(damnit!)
shizzle_______AutoCommand remote start : dual air horns
incomming___Hurricane F/R lower strut ties : Jeep TB : Field SFC Hyper-R

95 Eclipse RS : 5 speed
14.76 @ 94.72mph
Jeep TB writeup - http://www.dimensia.com:81/jimbo/JeepTBfor2gnt.html

>Can someone do this for this thread.
>It looks like neither Armond or I can.
>At the very least, can someone please
>clarify what-it-is that dictates the
>loop state(open or closed) on our ECU?

Ok today I did data log it for partial throttle and,

45-55% throttle
6-10psi
18-22 deg advance
EGT 1250-1300


I did this several times and always got the same result. The advance would go right to 22 and then drop down to 19.5-18. A few times it would drop lower to around 16 deg. But everytime it would go to 22 deg for a moment right away.

I never saw it higher than 22 deg. under boost

WOT and 18psi I get 18-20 advance.

What do you mean by clarify what dictates the loop state?

Throttle position is how the ECU knows when to go close and when to go open loop.

Brian

>>Can someone do this for this thread.
>>It looks like neither Armond or I can.
>>At the very least, can someone please
>>clarify what-it-is that dictates the
>>loop state(open or closed) on our ECU?
>
>Ok today I did data log it for partial throttle and,
>
>45-55% throttle
>6-10psi
>18-22 deg advance
>EGT 1250-1300
>

Interesting in deed. Looks like when MAP reading get maxed out, regardless of being in closed loop, timing comes down to 18-22 degrees.

>I did this several times and always got the same result.
>The advance would go right to 22 and then drop down to
>19.5-18. A few times it would drop lower to around 16 deg.
>But everytime it would go to 22 deg for a moment right away.
>
>I never saw it higher than 22 deg. under boost
>
>WOT and 18psi I get 18-20 advance.

Still seems just a bit high for that much boost pressure, but if you got no detonation, than thats awsome. That much timing without detonation makes some good power.

>What do you mean by clarify what dictates the loop state?
>
>Throttle position is how the ECU knows when to go close and
>when to go open loop.
>
>Brian

Ditto. From your tests, looks like the ECU retards timing back from almost 30 degrees under vacum conditions, to around 16-22 degrees advance at WOT. The MAP most def controlls this. I would *think* that if you ran the missing link, that you would get just a tad bit higher timing advance at WOT, around 18-22 degrees max. This is because it keeps the MAP at its max voltgage of 4.5 volts (at 0 psi). If you use the VC2 or other, it can keep the voltage a tad bit higher (4.7 volts or so, compared to the missing link max voltage of around 4.5 volts). This means that with a slightly higher map voltage under boost, that the ecu will pull just a bit more timing, closer to 16-18 total degrees of advance. Make sense? Theoretically, it would be *safer* to use the VC2 or other device to get a bit higher voltage from the map other than 4.5 volts, as less voltage from the map will make for a bit more timing advance. If we go with armonds advice, just run it a tad bit richer if you use the missing link, to help avoid detonation. This *could* be why i detonated at 10 psi, that along with a slightly lean A/F ratio. Makes sense anyway.. I use the missing link. Our stock maps are supposed to read about 4.5 volts at 0 psi, as the missing link keeps any boost pressure from the map sensor, which is why the missing link makes the map see an exact 0 psi all the time under boost.

I'm REALLY interested to know at what exact MAP voltage does it make the ecu go into fuel cut. If we knew this, then maybe we could adjust our WOT timing advace acording to map voltage AFTER 4.5 volts on up to the max voltage the ecu can accept. It would be interesting to see if we can get more timing retarded after 4.7 volts on the map. I think this could be very useful to do for people running 18+ psi. This way, we wouldnt have to use ANY timing retard units. Just raise the map voltage slightly, and the ecu pulls a tad bit more timing. Any thoughts??

13.5 @108 MPH-2.2 60ft(stupid FWD!)
S16G @ 18 PSI/FMIC/Running on MegaSquirt II (Now with sequential
fuel injection)
My webpage: http://eclipsed4evr.home.comcast.net
-1998 Mitsubishi Eclipse RS-T- "Toy"
-1992 Plymouth Laser Turbo AWD(SOLD)
-2000 Honda CR-V(daily)

I think that fuel cut is based more on injector pulse width than manifold pressure, and here is why. most all HRC stage 2 cars with stock injectors and the rising rate fuel pressure regulator hit fuel cut if they hit boost without a little black box or a vc-whatever or a missing link. think about what the nong term fuel trim is..........zero. the fuel pressure under vaccuum and at idle is just like factory, so while the ecu is reading the peripherials, it detects no need for leaning out the entire fuel map. when you run boost on it, the ecu uses a fuel map which is "quite enriched" past 4250 rpm and is basically a linear progression based on rpm and throttle position. the main reason i say this is on MuRiX's car............there is no fuel cut defense device..............and also no fuel cut . it however DOES go into a different fuel map once it hits boost, which is "very" evident after 4250 rpm between 0 and 4 psi (it shoots so much fuel per air that it won't burn). after 5 psi, the air/fuel mixture gets into a burnable range, and the car makes power. the air/fuel ratio seems to be slightly dependent on boost pressure, which leads me to beleive that it runs on a static base map in boost, and it seems to enter the "danger" zone at about 18+ psi with this map and 93 octane fuel and 525 cc injectors with -25% longe term fuel trim and 63 psi of fuel pressure. if the fuel pressure was higher, it would be consistantly safe, but the regulator the car is equiped with is non adjustable. all I say is if you have relatively large injectors, try zeroing out all your adjustment devices, and lower your fuel pressure so that it doesn't skyrocket under boost, and you jsut may never have fuel cut again. it's based on injector pulse width imho.

A.D.P.
"...If you do too much, people become dependant. If you do to little, people loose hope. If you do it right, people won't be sure you've done anything at all."
bring it on............

A.D.P.
"...If you do too much, people become dependant. If you do to little, people loose hope. If you do it right, people won't be sure you've done anything at all."
bring it on...........

Let me see if i can understand what you are saying here.

>I think that fuel cut is based more on injector pulse width
>than manifold pressure, and here is why. most all HRC stage
>2 cars with stock injectors and the rising rate fuel
>pressure regulator hit fuel cut if they hit boost without a
>little black box or a vc-whatever or a missing link. think
>about what the nong term fuel trim is..........zero. the
>fuel pressure under vaccuum and at idle is just like
>factory, so while the ecu is reading the peripherials, it
>detects no need for leaning out the entire fuel map.

So you are saying stock injects, with a map voltage greater than the 4.5 volts, when as soon as it sees boost pressure, the ecu is maxing out the pulse width? (assuming no cut device is on the car)By putting on a cut defenser or ML, that it keeps the ecu from making the injectors run at max pulse width? I guess i just dont understand fully what you are trying to say..


when
>you run boost on it, the ecu uses a fuel map which is "quite
>enriched" past 4250 rpm and is basically a linear
>progression based on rpm and throttle position. the main
>reason i say this is on MuRiX's car............there is no
>fuel cut defense device..............and also no fuel cut
> . it however DOES go into a different fuel map once it
>hits boost, which is "very" evident after 4250 rpm between 0
>and 4 psi (it shoots so much fuel per air that it won't
>burn).

What do you mean by this? Does his car barely run at 0-4 psi?

after 5 psi, the air/fuel mixture gets into a
>burnable range, and the car makes power.

By this, i am assuming that he is running fuel pressure almost the same at 0-4 psi, as it is under vacumm ?


the air/fuel ratio
>seems to be slightly dependent on boost pressure, which
>leads me to beleive that it runs on a static base map in
>boost, and it seems to enter the "danger" zone at about 18+
>psi with this map and 93 octane fuel and 525 cc injectors
>with -25% longe term fuel trim and 63 psi of fuel pressure.
>if the fuel pressure was higher, it would be consistantly
>safe, but the regulator the car is equiped with is non
>adjustable. all I say is if you have relatively large
>injectors, try zeroing out all your adjustment devices, and
>lower your fuel pressure so that it doesn't skyrocket under
>boost, and you jsut may never have fuel cut again. it's
>based on injector pulse width imho.

I have the 315cc injectors in my car, and datalogged it to fine tune. I run an idle fuel pressure of 25 psi. This keeps my short term fuel and long term fuel trims much below the -25%, and closer to the stock fuel map. It stays like this while normal engine vac driving, and part throttle, closed loop, low boost. I was getting around 75psi of fuel at 8 psi of boost. EGT's were good, not over 1575. A/F was around .93-.94 at WOT in 3rd gear. At ANY idle fuel pressure above 25 psi, i would get a too rich CEL. Short term fuel trims were almost pegged at -25%. So was long term. What are your thoughts of this? In your opinion, what is the max boost i can run with these injectors? I'm thinking 12-13psi with over 100 psi of fuel pressure.


>
>A.D.P.
>"...If you do too much, people become dependant. If you do
>to little, people loose hope. If you do it right, people
>won't be sure you've done anything at all."
>bring it on............

13.5 @108 MPH-2.2 60ft(stupid FWD!)
S16G @ 18 PSI/FMIC/Running on MegaSquirt II (Now with sequential
fuel injection)
My webpage: http://eclipsed4evr.home.comcast.net
-1998 Mitsubishi Eclipse RS-T- "Toy"
-1992 Plymouth Laser Turbo AWD(SOLD)
-2000 Honda CR-V(daily)

>So you are saying stock injects, with a map voltage greater
>than the 4.5 volts, when as soon as it sees boost pressure,
>the ecu is maxing out the pulse width? (assuming no cut
>device is on the car)By putting on a cut defenser or ML,
>that it keeps the ecu from making the injectors run at max
>pulse width? I guess i just dont understand fully what you
>are trying to say..
>


that is it exactly. when the ecu doesn't see 'max pressure' then the IDC is scalled up just like it woudl be if you were mashing out 140 hp out of the 235's. once you hit boost, the ecu knocks off abotu 5 degrees of timing and basically enriches the crap out of it on a new map. unfortunately, if the long term fuel trim isn't pretty low, teh new map stretches beyond 100% bringing another problem.......fuel cut. it's really 3 different things going on at the same time (at least that is what I gather from foolin around with it). stock map is going at it at probably 80% max duty cycle for non turbo maximum for the stock injectors and stock fuel pressure, then once you hit boost, you go into another pre-defined map........which stretches above 100% idc IF you are at 0% LTFT. at -25%LTFT, the "m.a.p. failure" map doesn't stretch beyond 100% idc anymore, so therefore, the ecu doesn't shut down the injectors. that is why you have to run "stupid" fuel pressure under boost and a fcd to run boost on the stock injectors. that way they won't hit 100% idc (stock fuel map) they won't throw a rich code (stock injectors, relatively stock fuel pressure) and they won't run lean (force feeding fuel through the injectors via pressure per boost).

>>
>What do you mean by this? Does his car barely run at 0-4
>psi?

exactly. it is soooooo rich from 0 to 4 psi between 4000 and 5000 rpm that it won't fire.


>
> after 5 psi, the air/fuel mixture gets into a
>>burnable range, and the car makes power.
>
>By this, i am assuming that he is running fuel pressure
>almost the same at 0-4 psi, as it is under vacumm ?

no. he has a 1:1 fuel pressure regulator with a base (0 pressure) set at 45 psi fuel pressure, so at idle (-7 psi or 14 in.hg) he has 38 or so psi of fuel pressure, and at 0 psi, he has 45 psi fuel, and at 5 psi he has 50 psi of fuel pressure.
>
>
>
>I have the 315cc injectors in my car, and datalogged it to
>fine tune. I run an idle fuel pressure of 25 psi. This keeps
>my short term fuel and long term fuel trims much below the
>-25%, and closer to the stock fuel map. It stays like this
>while normal engine vac driving, and part throttle, closed
>loop, low boost. I was getting around 75psi of fuel at 8 psi
>of boost. EGT's were good, not over 1575. A/F was around
>.93-.94 at WOT in 3rd gear. At ANY idle fuel pressure above
>25 psi, i would get a too rich CEL. Short term fuel trims
>were almost pegged at -25%. So was long term. What are your
>thoughts of this? In your opinion, what is the max boost i
>can run with these injectors? I'm thinking 12-13psi with
>over 100 psi of fuel pressure.

I think you are dead on. I would look into getting some bigger injectors. I know mark's car hit around 100 psi of fuel pressure with the 440 cc injectors at 20 psi (it was just a spike, but air/fuel ratio was still right where it was supposed to be. that s-fmu rocks). don't worry about running too low of fuel pressure. as long as yoru car runs, you are in the clear . mark's car idles perfectly at 10 psi of fuel pressure just to give you a hint . we logged it at the dyno, and I was like "wtf..........ok. that's new". the 420A is a neat little engine, and is pretty different from most things......that suck


>
>
>>
>>A.D.P.
>>"...If you do too much, people become dependant. If you do
>>to little, people loose hope. If you do it right, people
>>won't be sure you've done anything at all."
>>bring it on............

A.D.P.
"...If you do too much, people become dependant. If you do to little, people loose hope. If you do it right, people won't be sure you've done anything at all."
bring it on............

A.D.P.
"...If you do too much, people become dependant. If you do to little, people loose hope. If you do it right, people won't be sure you've done anything at all."
bring it on...........

I think you just proved we all have nothing to worry about. thank you .

A.D.P.
"...If you do too much, people become dependant. If you do to little, people loose hope. If you do it right, people won't be sure you've done anything at all."
bring it on............

A.D.P.
"...If you do too much, people become dependant. If you do to little, people loose hope. If you do it right, people won't be sure you've done anything at all."
bring it on...........

Cool


ride__________95 Eclipse RS : 5 speed
power________Gude cams : AFX UDP : ram air : test pipe : GST catback
suspention___BOMZ F/R upper strut bars : ES inserts
sound________Kenwood KDC 5000 : Audiovox 8" sub toob - no sub amp(damnit!)
shizzle_______AutoCommand remote start : dual air horns
incomming___Hurricane F/R lower strut ties : Jeep TB : Field SFC Hyper-R

95 Eclipse RS : 5 speed
14.76 @ 94.72mph
Jeep TB writeup - http://www.dimensia.com:81/jimbo/JeepTBfor2gnt.html

anvengers car with 440 injectors and idle fp at 10psi? dame,,, what was static and what disk/springs and all did you guys use ?... i also assume that only 'small' adjustments were made at HI th points..
hey armond wanna come to ca to build and install my engine..hehe i assume it easy and fun for you...
cool

Michael 99gs
HRC Stage 2
Stage 3 process begins anyone got a 420a block thats not spun/head for sale?

http://www.dreamwater.net/purplebeast

Michael
99gs hrc stage 5000 SOLD...
2004 Honda Accord V6 (240 hp)stock
what other car should i buy?? hmmm
Car info & pictures at http://www.cardomain.com/memberpage/520269

Why does Armond not get more + ratings on his profile like he deserves anyway??

My car is cool.

05 Mazda RX-8
06 Lotus Elise

Because if you do it right, people won't be sure you've done anything at all.


ride__________95 Eclipse RS : 5 speed
power________Gude cams : AFX UDP : ram air : test pipe : GST catback
suspention___BOMZ F/R upper strut bars : ES inserts
sound________Kenwood KDC 5000 : Audiovox 8" sub toob - no sub amp(damnit!)
shizzle_______AutoCommand remote start : dual air horns
incomming___Hurricane F/R lower strut ties : Jeep TB : Field SFC Hyper-R

95 Eclipse RS : 5 speed
14.76 @ 94.72mph
Jeep TB writeup - http://www.dimensia.com:81/jimbo/JeepTBfor2gnt.html

bingo

A.D.P.
"...If you do too much, people become dependant. If you do to little, people loose hope. If you do it right, people won't be sure you've done anything at all."
bring it on............

A.D.P.
"...If you do too much, people become dependant. If you do to little, people loose hope. If you do it right, people won't be sure you've done anything at all."
bring it on...........