I went to a friend today and hooked up a wideband to my car and did some runs....i have a adjustable FPR (accel 74566) turned @ 32 PSI idle pressure, gmsc 310cc injectors and a cartech 2025 FMU...and the results.......
Well if you guessed lean you would be right =( it was around 12.5 at 1-3 PSI but when i got to around 4 psi of boost it started climbing and around 5 PSI around 4500 RPMs i started to hit 15.0 on the wideband then we stopped. we decided it was the stock fuel pump that was holding me back..the fuel pressure read 75 PSI of pressure maxxed and wouldnt go no higher =( Im assuming that the over all fuel volume of the stock pump isnt pumping out enough.
Im gonna get a walbro 255 and see what happens after..but man!! for only 5 PSI non intercooled on stock exhaust..that @!#$er got up! hehe anyways....ill have a update in about a week or so...
Are you positive your FMU is working properly? Stock pump should work no problem with 5psi I would think. Are you able to check fuel pressure while driving? That would be the next step I think. If the pressure drops, it's the pump.
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we were checking fuel pressure....it would start to rapidly rise once hit boost and raise to 75 and drop a little to like 70...would not go any higher then 75
If it makes you feel any better my car runs a a/f ratio around 15 until 4800 and drops to 14 after, and thats without any boost.
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let me ask a stupid question...if i have a stock fuel pump running on these injectors at say 50 PSI and had the same injectors on a walbro 255 at 50 PSI...took both these setups and squirted all the fuel in a bucket ..will the walbro setup fill the bucket quicker?
Or does the walbro just allow you to run higher pressure rates with it? in my case above 75 PSI pressure? or does it do both??
Im learning as i go so please dont flame me for a noob question like this....
weird... totally weird, you should be fine
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just wondering. i looked in your profile
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accel AFPR #74566
where did u get that at? i wasnt aware there wasnt an ecotec AFPR out.
John H wrote:just wondering. i looked in your profile
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accel AFPR #74566
where did u get that at? i wasnt aware there wasnt an ecotec AFPR out.
Just because it doesn't list "Ecotec" in the applications, doesn't mean it won't work.
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for FPRs i always recomment Aeromotive just because they are the fuel system people. i've had problems with Accel parts in the past especially the Accel coils... *shudder* that project was a pain.
I was a retard, and now I'm permanently banned.
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Just because it doesn't list "Ecotec" in the applications, doesn't mean it won't work.
yeah i understand that, but what car is that fuel pressure regulator for?
74566. is that a summit number or what?
its from a LT1 but a early model..i cant remeber what year it said on the box..it was the EXACT same as the #74565 but the bracket that mounts it to the fuel rail is on the opposite side...and the fuel pressure was from 25-60 PSI where the #74565 is 35-70 PSI adjustable...ecotecs need the 74566.
my car w/o boost stays around 13.7 to 1 or so, Per wideband yesterday. at idle its like 16 to 1 ahahaha dayum stock fuel system
my friend has 320 cc injectors and 10 psi , and his a/f reads off the scale rich
so you have a obvious problem some where
well..everyone who runs boost almost 99.9% of people upgrade there fuel pump...so im gonna do it just becuase of that..
What else is your friend running for fuel managment.??..all i have if raising fuel pressure to increease fuel flow. im rich untill my fuel pump maxes out at 75 PSI of fuel according to the guage when we ran the car....i have no doubt thats my problem. If i run lean when i put my pump in....then ill have to start double checking everything..
I agree, something is not working . Get rid of the fmu and just try it with the 310's and the afpr. Thats what I had when I first ran my car. At wide open throttle on the 6psi i was exactly at 12.1 afr on my LM 1 wideband... It may run rich at idle with the 50 psi but at least u won't be lean. It may trip a CEL but it will only be for running too rich. And do yourself a favor and put an Intercooler on like right now. good luck buddy.
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stock exhaust too I just read. That really has to get upgraded. TIny exhaust is your enemy with turbo.
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well i gotta get the pump for future upgrades anyways..when i get it done ill screw around with the FMU some more since ill have a bigger margin to mess around with the new fuel pump. as far as intercooler and exhaust ..i know it needs to be done...
When we werer running my car that night...we did about 10 good runs on it and the charge pipe at the front (3 inch tube) at the TB wasnt even warm...which was surprising! Ill be ok without a intercooler for now..i dont plan on boosting any higher then im at now. The exhaust will be next on my list.
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my friend has 320 cc injectors and 10 psi , and his a/f reads off the scale rich
not tryign to thread jack, but whats your buddy got to control the 320cc's? im assuming its an ecotec? does he have an safc or can the stock ecotec ecu run a set of 320s?
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well..everyone who runs boost almost 99.9% of people upgrade there fuel pump...so im gonna do it just becuase of that..
On ecotec's I have not heard of anyone doing a intank pump upgrade. I know the stock fuel pump can handle 16-17psi of boost. Something is not right on your set-up. What disk are you running on your FMU.
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I agree, something is not working . Get rid of the fmu and just try it with the 310's and the afpr. Thats what I had when I first ran my car. At wide open throttle on the 6psi i was exactly at 12.1 afr on my LM 1 wideband... It may run rich at idle with the 50 psi but at least u won't be lean. It may trip a CEL but it will only be for running too rich. And do yourself a favor and put an Intercooler on like right now. good luck buddy.
You have to have a FMU to increase fuel pressure under boost. A FPR will not do it.
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When we werer running my car that night...we did about 10 good runs on it and the charge pipe at the front (3 inch tube) at the TB wasnt even warm...which was surprising! Ill be ok without a intercooler for now..i dont plan on boosting any higher then im at now. The exhaust will be next on my list
That is one of your reason you are running lean. Hotter air needs more fuel to cool it down. YOu need to turn up your FMU so it brings the fuel pressure up more. If you intercool it, this will make your tunning much easier.
FU Tuning
Ive been pondering on what we were doing that night and i came to one suggestion...
when i reached almost full boost (5 PSI) we were maxxing out the pump (75PSI) ..im thinking we had too much PSI then we needed. i leaned when the pump maxed out...so i think i had the FMU turned up to high..we never tryed turning it down..only up =( which was our mistake...
Im think if we could have got the fuel pressure gauge to read maybe 60-65 ish fuel pressure at max boost we would have kept our richness...we started with the FMU at half way point and adjust up which was wrong =(..i think the FMU was kicking out maybe 8:1 PSI + at half way when we needed lets say 4:1..once the pump maxed out it may have spike or stopped pumping out the consitant fuel therefor reading lean on the wideband..becuase when it hit 75 PSI on the gauge it spiked down to 70..
i watch the fuel gauge and once he hit boost that thing shot up fast...im think too fast =(
so maybe i dont need a fuel pump but..i bought one today anyways and i rather go back prepared...ill let you guys know at the end of the week how it went...
oh ..and to answer you question on the FMU..John Higgens...i have a adjustable Cartech..no disc's...
also what i meant on the cool 3 inch pipe at my TB....i was saying it wasnt warm at all ther-for i beleive the air going in wasnt really that Hot as you may think...im fine running how i am w/o a intercooler atm...
hey John maybe you should read my post again. I said that you turn up your fuel pressure at idle to 50 or so psi which will be rich for idle pressure , but will compensate for when you are under boost giving you a descent a/f ratio. That is for a 2.4 though. Don't know how much you will need to adjust it for ecotec apps.
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I was gonna say, 75psi of fuel for 5psi of boost!? That's a bit much, but then I thought maybe the Turbo cav's are different..
With my car(non-cavy), the idle pressure is 37psi, with a stock 1:1 FPR at 15psi of boost, I have 53psi of fuel... I'm also dealing with just under 1650cc's of fuel though.. Soon to be 2100cc's total..
Dunno if that helps any, but there it is anyway..
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hey John maybe you should read my post again. I said that you turn up your fuel pressure at idle to 50 or so psi which will be rich for idle pressure , but will compensate for when you are under boost giving you a descent a/f ratio. That is for a 2.4 though. Don't know how much you will need to adjust it for ecotec apps.
I have 2 2.4's one of which is boosted. Non-intercooled. Stock fuel pump, with a booster pump inline. 50 psi at idle is not enough fuel for boost. More so non-intercooled.
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I was gonna say, 75psi of fuel for 5psi of boost!? That's a bit much, but then I thought maybe the Turbo cav's are different
No he is non-intercooled. We are pushing 80 psi of fuel with 360cc injectors. Intake temp is about 243 in the summer before getting to the motor.
FU Tuning
