For those of you that don't know here is a small breakdown of what I have:
built bottom end: 8.6:1 JE Pistons, Crower Rods built head: Ferrera (sp?) valves, stage 5 porting (upper and lower intake mani, TB) Star Stage 2 turbo kit with FMIC Complete stand alone fuel system (Aeromotive 1000HP fuel pump, bigger fuel rail with one feed line and one return line) Fuel pressure regulator and SAFC for tuning 415 CC injectors
I just got the head work, the fuel system, and a 3.5" exhaust this weekend. And I need to tune it. When I get on it, my EGT's are out of control. Way above 1600.
Here is the deal, I am trying to find someone in Austin to help me tune. One guy said that I need bigger injectors? Do you think that I do? If so, what size? Thanks.
You actually shouldn't need bigger injectors if you have you an adjustable FPR set to the appropriate ratio, with something to the tune of 3:1-4:1, I'm guessing.
Does your A/F meter reflect the high EGT's as well? Sometimes overly rich conditions can reflect high EGT readings. That's why the only way to really tune accurately is with EGT's, A/F meters, and a datalogger to monitor timing.
If you are truly lean, and you're receiving adequate fuel supply TO THE INJECTORS, then it's something electronic such as the S-AFC, map sensor, or any FCD device you may have.
But take it one thing at a time, make sure you're at least making available to your injectors the right amount of fuel (or fuel pressures).
_____________________________________ Jason ESi-T
04' BMW 325Ci 91' Nissan 240SX 98' Eagle Talon ESi (sold)
#34345, "RE: Need some advice and help inside...." In response to Reply # 0
what are you a/f readings? since you have the star kit I take it you have an fmu. did u upgrade to an sfmu? what disk are you running... there are quite a few variables you should check. mainly your a/f to see if you are running pig rich or too lean. after we know that, we can work from there.. I don't think your injectors are too small.
-97 GS (First project, 299 whp)(sold) - 97 RS 2.6 last numbers: 306hp, 352tq @16psi (Dead, parted out) - 99 GS OZ, Hahn Kit, 56k miles (Sold) -------- - 00 Nissan Maxima GLE (Daily Driver) - 02 Audi A4 1.8T Quattro
#34346, "RE: Need some advice and help inside...." In response to Reply # 2
Nope...
I have a new fuel pump that runs from the tank to the fuel rail. From the other side of the rail to a regulator, then back to the tank. I have my idle fuel pressure set at 52 psi. I do not know what it is under full boost because I do not have a guage in the car.
I am not sure about my A/F becuase usually under full boost I am looking at my sky rocketing EGT's. I have a feeling it is in the .94 range. But I am not positive.
I think that I am going to have a couple local DSM guys help me on Saturday to tune. They are 4G63 guys, but I won't hold that against them. They have a data logger and we are going to use that to help tune.
Hopefully I will be able to turn the boost up this weekend. }>
#34348, "RE: Need some advice and help inside...." In response to Reply # 4
How much boost are you actually trying to run and what fuel pressure are you getting are the two most important questions. Without that, no answer is going to be accurate. I can make a pretty good guess now though that you will need bigger injectors.
#34349, "RE: Need some advice and help inside...." In response to Reply # 5
>How much boost are you actually trying to run and what fuel >pressure are you getting are the two most important >questions. Without that, no answer is going to be accurate. >I can make a pretty good guess now though that you will need >bigger injectors.
Definitely need this info in order to help...
Also, if you're still running the vortech 12:1 fmu, you should be really rich shortly into boost w/ 415cc injectors. I'm guessing your "nope..." was the answer to whodatt asking if you had the SFMU. If that's correct, you need a smaller rise ratio as Jason said.
#34350, "RE: Need some advice and help inside...." In response to Reply # 6
OK... let me try to explain my fuel setup again.
I have a HUGE external fuel pump. It pulls gas from the tank and connects to one side of the fuel rail. The other side of the fuel rail goes to my 1:1 FPR, which has a vaccum line going to the mainfold. From there it goes back to the tank.
Now having said that, I have my idle fuel pressure set to 52 psi. So since my FPR is a 1:1 ratio, at 12 psi my fuel prssure should be 64 psi. I say should be because I do not have a fuel pressure gauge in the car, not yet.
So does that help? Now do you think I need bigger injectors?
#34353, "RE: Need some advice and help inside...." In response to Reply # 9
So Murix from what you are saying it is actually better running 50lbs injectors with a 1:1 like reguar gst run than running 35lbs injectors with Rising FP.
Now i think that using the 1:1 is better simply beucase the duty cycle will be lower than running the 35 with more pressure correct or not ????
#34354, "RE: Need some advice and help inside...." In response to Reply # 10
Running higher ratio FP's is always a layer below versus having larger injectors (that run 1:1 ratios) because of the extra variables that are necessary to raise fuel pressures, the very slightly slower response time to the added fuel, and lastly the lesser amount of tuning resolution that is available in merely rising the fuel pressures rather than varying the injector duty cycle.
However, the lower the fuel pressure ratios, the less that difference becomes much of a recognizable deficiency.
_____________________________________ Jason ESi-T
04' BMW 325Ci 91' Nissan 240SX 98' Eagle Talon ESi (sold)
#34355, "RE: Need some advice and help inside...." In response to Reply # 11
I believe his gauge is fooked.
I've seen Brynden lay into the car with the EGTs pegged by halfway through second and not let off until the end of third. There is no way that would not do damage over seveal months, yet when we installed the new head, internally everything was perfect. No signs at all of excessive heat on the pistons or exhaust valves. No pitting in the head, no signs of detonation. In fact, it looked more like it was running excessivly rich - really thick carbon on the pistons, no white burn-in on the turbine wheel (it was a colder brown). If isn't afterburn, either, as leaning it down doesn't help (even drastically leaning it down). Everything i see points to either a busted gauge or 7 degrees of advance at WOT - but the car PULLS, so i doubt it is so much a timing issue.
I'm stumped, and until that guage reading is verified, i'm skeptical that an EGT issue exists.
______________________________ If a sentence found online has 35% misspellings or greater and includes at least two racially charged expletives, chances are it is a YouTube comment.
'95 Eclipse TurboGS (garage deco) '95 TSi AWD (restoring a survivor) '97 Talon ESi-T (poor impulse control) '99 Eclipse RS-T (daily beater) '13 Evo X (mostly stock) '17 Sienna (Middle Aged Dad Mobile)
#34356, "RE: Need some advice and help inside...." In response to Reply # 12
I would have to believe he is waaay lean with a 1:1 fpr and 415cc injectors. The fuel pressure can't be high enough under boost to compensate. I'm running 65lbs of fuel pressure under boost with 625cc injectors and a 1:1 fpr. I would do the math on Corbins fuel page and see if your setup is anywhere close, and if not what needs changed.
Greg
'19 Genesis G70 3.3t AWD '88 Chrysler Conquest TSI
#34357, "RE: Need some advice and help inside...." In response to Reply # 13
>I would have to believe he is waaay lean with a 1:1 fpr and >415cc injectors. The fuel pressure can't be high enough >under boost to compensate. I'm running 65lbs of fuel >pressure under boost with 625cc injectors and a 1:1 fpr. I >would do the math on Corbins fuel page and see if your setup >is anywhere close, and if not what needs changed.
hey what is your fuel setup i am leaning on going with higher injectors than a raise FPR. Maybe you can give me some ideas ?
Assuming, you're only running 1:1 fuel pressure, who knows what your duty cycle is maxing out at. But basing you duty cycle on 100% certainly can't be expected. Remember, the stock 4g63's have stock 450cc's with a 1:1 FP. With that ratio, you have to be thinking about same or similar sized injectors as they do for more HP.(i.e. 550cc and higher)
_____________________________________ Jason ESi-T
04' BMW 325Ci 91' Nissan 240SX 98' Eagle Talon ESi (sold)
#34359, "RE: Fuel system calculations...." In response to Reply # 15
Ok, so what is the down fall of getting too big of injectors? I was thinking about getting 625's or so. Is it possible to have injectors that are to big? What are my potential problems?
Thanks for the help guys.
Oh and I have some local 4G63 guys coming tomorrow to data log my car. How can we tell if the injectors are maxed out? Is there any way to tell with the data log software?
#34360, "RE: Fuel system calculations...." In response to Reply # 16
If you go too big, you'll need different fuel control (ie. DFI, e-manage) etc. The stock ecu can't handle 625's, even with an AFC. Maybe you should look at the 8 injector setup, or at least the e-manage. Anything else will put you well over $1000, not to mention starting all over again with your tuning.
I have 625's, HRC's in-line pump, and a 95 fuel rail that has a 1:1 regulator built in. The DFI runs it all, and I have a base fp of around 45psi (stock) and go 1:1 from there.
Greg
'19 Genesis G70 3.3t AWD '88 Chrysler Conquest TSI
#34362, "RE: Fuel system calculations...." In response to Reply # 18
..but here's a kicker, guys -
His car did the exact same thing on 415's with a 4:1, which is why i don't beleive it's necessarily a fuel problem.
______________________________ If a sentence found online has 35% misspellings or greater and includes at least two racially charged expletives, chances are it is a YouTube comment.
'95 Eclipse TurboGS (garage deco) '95 TSi AWD (restoring a survivor) '97 Talon ESi-T (poor impulse control) '99 Eclipse RS-T (daily beater) '13 Evo X (mostly stock) '17 Sienna (Middle Aged Dad Mobile)
#34364, "RE: Fuel system calculations...." In response to Reply # 16
>Ok, so what is the down fall of getting too big of >injectors?
Too big of injectors create problems for off boost operation and idling. Why? Becuase your stock ECU can't lean out the injectors enough to where you're flooding your cylinders with gas.
I was thinking about getting 625's or so. Is it >possible to have injectors that are too big?
Only if you can't lean them out during low rpm operation.
What are my >potential problems?
Being able to afford and customize a fuel system that will meet your boosting needs.
>Oh and I have some local 4G63 guys coming tomorrow to data >log my car. How can we tell if the injectors are maxed out?
Datalogging would be a big help. You can do a variety of things with a datalogger that can indicate what you're current fueling needs are. I don't know if it's possible, but if you can maintain low TPS operation so you stay closed loop, you might be able to tell if your car is needing more fuel through the fuel trims indicating a overly positive number (+19-25). Also, you'll be able to monitor your O2 readings from your datalogger. In any case, I woudl try and knab a A/F meter as soon as you can to at least make sure it works. If you have a bad O2 sensor, that can create ALL sorts of problems with your fueling.
> Is there any way to tell with the data log software?
It won't come out and say if your injectors are maxed out, but it will give you other information relative to your O2 readings and timing advance that may prove helpful in giving you clues.
There is a product that I have considered buying that actually monitors your injector duty cycle. I'd like to have one myself for my four secondary 440cc's that I run.
_____________________________________ Jason ESi-T
04' BMW 325Ci 91' Nissan 240SX 98' Eagle Talon ESi (sold)
#34365, "RE: Fuel system calculations...." In response to Reply # 21
Hey, well with Safc you could actually control 620cc injectors from what i have seen. My buddies that have 4g63 are running on them good with safc and can control them well.
But they are -40% to -45% so there is a problem. Timing issue again there will be a messed up there with the map.
If one does not have the money for stand alone them might as well go with the injectors that you have now the 420cc and Sfmu.
Search
Printer-friendly copy
0 Users in Chat
