Ok guys, I need some tuning help. I've got all the big power parts I am gonna do for awhile, but they aren't sh!t w/ out proper tuning as you know.

I am going to get probably 2 hrs of dyno time setup within the next few weeks while I am between semesters.

I have a guy that knows a little about tuning stand alone units but has never tuned a DFI. So, Any help you all can throw at me would probably do wonders.

When tuning the DFI (w/ Calmap software) what A/F with a wideband should I be trying to obtain? Should I be trying to obtain that A/F whenever I am at WOT, or should that be when the boost is up to whatever level i have set it for?

When changing values on the fuel map, should I feather the cells around the value(s) I change to smooth it out?

What about the MSD DIS-2? Right now I have it set to not pull any timing. I dont get detonation at higher boost levels, but how do I tune this thing on the dyno to get out of it whatever i need?

I have the 2 step rev limiter set pretty low, maby 3800-4000 rpm, not sure exactly, but when i hit the button and mash the gas, all I get is *bam* *bam* backfiring like a damn .308 rifle, and I know thats not good.

If I want to tune high boost levels, should I run race gas? And if I do, when tuning lower boost levels, will that mess me up when I am just running around town on premium, which is usually what I do.

What about cam gears? I dont believe I have any headwork down, but the engine was built before I bought the car.. So should I just tune the cam gears a little at a time and dyno between each setting and see whats the best powerwise?

Also, anything else you all think of that I forgot to mention, please feel free to help me out.. I am a newbie when it comes to tuning on a dyno..

Feel free to tell me to do some runs with the obd-2 thing hooked up and datalogging if it helps you with any suggestions. Just tell me what to record and I'll try and get the files posted or emailed.

TIA

>I have the 2 step rev limiter set pretty low, maby 3800-4000
>rpm, not sure exactly, but when i hit the button and mash the
>gas, all I get is *bam* *bam* backfiring like a damn .308
>rifle, and I know thats not good.

that my friend is your launch control, burnout box setting. basically its for heating up your tires in the burnout box at the dragstrip.

i.e heating up your slicks

pull to the water, or box

activate your limiter,

when the tires get hot, smoke pours, and you feel it catch traction, let go, and hesitate on the gas, and pull on out the box, or smoke. ;)

there you have sucessfully heated your tires with out causeing any kinda engine damage. also pretty cool feature to call someone out, thas what i use my launch control for.

and it doesnt do any damage to my knowledge, maybe for prolonged use of course. but it drops the cylinders one at a time.

well i answered one of your questions, im in the blue when it comes to dyno tuning also, and i really dont know much about a dfi, i will direct armond to this post though.




DWAYNE H


www.gottude.com
Red/Black/Silver 01 GSXR 750
Lots of Apexi components...

The stutterbox feature (the first stage of a 2 stage rev limit) is used on a launch, to set the revlimit to whatever you wish to launch at. If it is set to 4500RPM, then mashing the gas will keep the engine at 4500 RPM. This lets you keep an eye on the tree and get the best R/T possible. It also makes your launches more consistant. And I would feather the cells with the DFI to keep things flowing smoothly, rather then have jagged peaks. Change individual cells only if you need to. Cam gears should also be tuned a bit at a time, as they typically have a bell curve to them, meaning that at one setting, they are making less then optimal power. Advancing 3 degrees may make optimal power, but advancing 4 degrees will bring you back (power-wise) back to where you started. So try small steps for the gears, and stick to what makes the most power. At the least, log A/F and RPM. I think that your beast should be tuned in fourth gear, too, by the way. I have never ridden in it, but that is my guess based on the power that you will probably make.
My .02 cents (yup, 2/10 of a cent), and, as always, your results may vary. Use only as directed. If headache, sweating and death continue, stop using and see a physician. Offer not valid in Michigan, Canuckistan, and Arizona.
-=B-=

Well, I know how to use and abuse the 2 stage rev-limit, but I cant use it because it just loads up on fuel and backfires massively to the point where it just shoots a long flame and a cloud of black smoke. It doesnt just studder at a specified RPM, and if I try to use it it just bogs down... right now i am better off dumping the clutch.

I guess I'll pull the codes from the datalogger and see if I am off a tooth on the timing but I just did the t-belt not too long ago to try and fix that.

I'll try to email armond to see what kind of a/f it is best to tune @, cause I know he's done his fair share of dyno time.

Please post the dyno numbers , I think u have the fastest car on the board.


http://www.BerkshireCountyImports.com

11.5:1 seems to be the happy ratio, from what I have seen.
-=B-=

>Well, I know how to use and abuse the 2 stage rev-limit, but
>I cant use it because it just loads up on fuel and backfires
>massively to the point where it just shoots a long flame and a
>cloud of black smoke. It doesnt just studder at a specified
>RPM, and if I try to use it it just bogs down... right now i
>am better off dumping the clutch.
>
>I guess I'll pull the codes from the datalogger and see if I
>am off a tooth on the timing but I just did the t-belt not too
>long ago to try and fix that.
>
>I'll try to email armond to see what kind of a/f it is best to
>tune @, cause I know he's done his fair share of dyno time.

You are too lean in that area... richen the mixture, ie, dump more fuel in that area. Theres a few ways u can do this... not sure how yer standalone works

I wonder who has the fastest car, Super20G, Brynden's 2.4L or Dino?

Good question, but off topic.

:-(

Well Steve from Performance Distributor is working on a custom 420a distributor for DFI 6's off the cam angle sensor, so maybe you wont need all that other stuff later on. There about a month away for having it. There # is 901-396-5782

>My .02 cents (yup, 2/10 of a cent)

That is 2/100 (1/50) of a cent, btw. ;-)

Super20G, do you have an EGT sensor?


-=Whittey=-

yep, gotta have the egt gauge.

>When tuning the DFI (w/ Calmap software) what A/F with a
>wideband should I be trying to obtain? Should I be trying to
>obtain that A/F whenever I am at WOT, or should that be when
>the boost is up to whatever level i have set it for?
>
>When changing values on the fuel map, should I feather the
>cells around the value(s) I change to smooth it out?

I agree with Bill. You should feather the cells to keep a smooth curve on the fuel map, and change the individual cells only if needed.

Remember with fuel, start off on the rich side so you don't risk detonation, then go from there.

>What about the MSD DIS-2? Right now I have it set to not pull
>any timing. I dont get detonation at higher boost levels, but
>how do I tune this thing on the dyno to get out of it whatever
>i need?

You need to pull timing to prevent detonation. It's tuning for safety. Since you have a very serious setup, wtih alot of money invested into it, I would again error on the safe side and pull several degrees of timing or so just to be sure. Then, with everything else remining constant, nudge it up a few degrees, keep an eye on knock/detonation/the car's computer pulling your timing. If you get knock, or the computer does pull timing then back off those few degrees.

>If I want to tune high boost levels, should I run race gas?

Tune for race gas if you are going to use it at the strip. If you don't plan on spending the $5+ for race gas, then just tune for pump gas. I know people who run low 12s and such on AWD DSMs and pump gas, so you can make power with it, but the extra octane in race gas does let you tune high boost applications more effectively.

>And if I do, when tuning lower boost levels, will that mess me
>up when I am just running around town on premium, which is
>usually what I do.

My best guess here is no, not if you keep the boost levels rather low. At part throttle not much will change.

>What about cam gears? I dont believe I have any headwork
>down, but the engine was built before I bought the car.. So
>should I just tune the cam gears a little at a time and dyno
>between each setting and see whats the best powerwise?

First off, I would do cam gear tuning LAST, after you get the A/F ratio and timing correct. The changes from cam gear tuning will be small for your application (which is why most turbo DSM guys don't bother with it, they just put in big HKS 272 cams and are done with it), so I would do it last. Also, it just makes sense to make sure the more critical settings (fuel/boost/timing) are set before cam gears.

Now, what you should do depends on many factors, including how much time you have to do this with, but since you have only so much time what I would do is start at Intake/Exhaust (+ is advnace, - is retard) 0/0, then go +5/0, then -5/0. Then go 0/+5, 0/-5. Then go +5/+5, +5/-5, -5/+5, -5/-5. This covers every possible combination at 4 degrees.

I chose 5 degrees because this should be enough of a change in the gears to see a difference in the power curve, but not so big as to push you over the edge and see an actual loss (as Bill was mentioning, which does happen). Now, as you can tell, you could do ALL of this at 1 degree increments, then 2 degree increments, then 3 degree increments.... but that would take forever. This is one of the problems with cam gear tuning! You can spend alot of time chasing a little bit of power.

In my opinon, it's better to start off with a fairly big change (not a HUGE change! +5 degrees isn't huge) and seeing where that places you, then fine tuning the settings. (In other words, first "paint with a big brush" then fine tune from there)

For example, from the settings I described above, you can see which give you the optimal torque curve for what you want from your car, (let's say it's +5/-5) then you can go +6/-5, see what that does, then +4/-5, and go from there.

>Also, anything else you all think of that I forgot to mention,
>please feel free to help me out.. I am a newbie when it comes
>to tuning on a dyno..

Remember, the absolute numbers on the dyno are NOT important! The comparison between one run and the next IS important.

TREAT IT LIKE A SCIENCE EXPERIMENT! (Which it really is, when you think of it.) Go through the tuning in a logical, step by step matter. CHANGE ONLY ONE (1) THING AT A TIME, then do a run, then change ONE THING, then do a run. If you change more than one thing between dyno runs, then you won't know which change actually helped, and which actually hurt performance.

Remember: One thing at a time!!!!

Also, concentrate on the TORQUE curve, not the hourspower curve. Too many people will focus on the hp because they want to see a high peak number, but that isn't the best way to tune your car. HP is just torque over time. Compare torque curves to torque curves; you can see the changes and details of what you are doing (especially at lower rpms) better by looking at torque. If you make a change that gives you more torque at 7000 rpms, your horsepower will be higher at 7000 rpms, so don't worry about HP, it will take care of itself if you just keep an eye on that torque curve.

>Feel free to tell me to do some runs with the obd-2 thing
>hooked up and datalogging if it helps you with any
>suggestions. Just tell me what to record and I'll try and get
>the files posted or emailed.

Record everything you can that the logger can handle. Since it's OBD2 you can't get much (low singal rate) so make sure you look at timing, rpms, long term and short term fuel trim values, and O2 sensor voltage.

Now, if you're on a good dyno, they will have a wideband O2 sensor in your tailpipe, so technically you won't need to bother with the stock O2 sensor. But, I think it's a good idea to get some comparisons between your stock O2 sensor and the wide band, so you have an accurate reference when you tune on the street/at the track with your stock O2 sensor.

If the logger can handle it, and you get good enough resolution, I'd also look at air/water temperature, but these probably aren't a priority.


Hope that all helps!

Thanks for the info.

I will definately tune everything seperately and one step at a time.

Thanks for the cam gear ideas, I'll play around with that last, right now they are both set to zero.

I might take a few gallons of race gas to tune higher boost if I have time..

I dont have the oem o2's hooked up, so I wont be able to datalog that stuff, but I will get timing and rpm and all the other.

Does anyone have any ideas for why my 2 step rev limit backfires instead of holding a constant rpm? Hopefully after pulling some fuel out of the base map that will go away.

So, on the ignition... i should pull a little timing? At what rpm should I start pulling? and can i datalog it and see what kind of advance i am getting, then advance it some more until i get some good numbers? if so, what are good numbers to be looking for w/ out melting a piston? hehe

I am trying to get more power out of this engine, get it running smoother on cold starts, and also play it a little safe cause the last thing i need to do is pull this engine back out.

Don't pull any timing. If you have to pull timing to keep from knocking on pump gas, you're running too much boost or too low a grade of fuel for your application. (As in, you need to either turn the boost down a hair or start mixing in racegas). Use the MSD's timing retard feature only as a last resort, to squeeze those precious last few HP out of pump. IMO, though, that's just too much effin work.

^^^I agree with Dino on this. I had fairly recently helped set up an R/T neon running stage 5+ after he changed from the gen 6 to a gen 7 DFI. We at first looked into making an adapter plate with the other needed supporting hardware to convert over to an "old school" 2.2L distibutor so we could dial in timing changes on the fly...rather than use the MSD.. this all went way side for the time being, that he was able to put down a little over 360 whp and 340 ftlbs on a 94/112 leaded mix with the Super 20g and allowing his Profec B to keep track of boost.. His a/f was tuned for consistantly being between 11.3 - 11.5 to 1 from 3500 rpm to 7200. I can see about getting the graph for you to look over... However I still haven't been able to attach an image of my car in my sig.. LOL ;)








420a and ej20... both with boost

If you dyno with race gas, you will be too lean when you go back to pump unless you create 2 maps. I had a map for the track (race gas) and one for the street (pump gas). Unless of course you are going to run whatever you dyno with all the time. :7

The new AFCs have separate maps for street/strip.


Jon

1997 Eclipse RS

13.887@104.648 5/30/03

www.haiokuracing.com