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Discussion Starter · #1 ·
Alright so like everyone else on here i went to the track..... after almost a year of the car not running, i have been driving it for about 4 weeks breaking in all the mods, and i know that the car needs to be tuned VERY VERY BADLY. but i was not expecting this......... I had the car running at like 32psi base fuel pressure and the safc tuned at -2 all across the board assuming that the car is supposed to run close to spec with the lex, 550's, that was not the case, my car would not rev past 5,000 rpm, Im thinking Wtf I am hitting fuel cut with 550's. So then i tuned it to 40psi and 0 on the safc, and it wouldn't rev past 4300 rpm....... then finally i dropped the fuel pressure to 35psi and turned the safc down to -11 and the car could rev pretty high about 5800 rpm. I ran two 17's and finally a 15.9 with it reving to 5800 this was really embarassing!!!.. I know I should have done A LOT better because with a RT of .023 and 60' of 2.035 YOU JUST DON'T RUN 17's.
I am planning on getting the car tuned ASAP but was wondering what all your cars are tuned at? how lean is your safc? What Base fuel pressure are you running? im looking for details that i can compare. BTW I was running 14 psi the whole time.
any comments, ideas, rude remarks?
Thanks in advance~ Steve
 

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when this baby hits 88mph
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reaction time has no effect on et/mph. but nice rt :)

base fuel pressure is gonna depend heavily on your particular car. when you quote the above pressure was that with or without the vac line connected? w/ the vac line ON its gonna read ~8psi lower vs w/ it off.

how i tune mine is get the a/f curve flat as possible, then move the entire curve up or down to get desired a/f by adjusting base fuel pressure up and down.
on my car w/ upgrade ct, walbro pump, lex afm w/ screw all the way out, 580cc i had -5% up to 4k. 4k to 5k was -9% and 5k to 6.5k was at -14%. base fuel pressure to get 11.9 across the board was 33psi w/ the vac line OFF.

just be very careful adjusting the fuel trim w/o the proper devices. also to note, a boost leak will effect your a/f as well. the more serious the boost leak the richer it is going to be. keep that in mind as well. i would check over all my ic piping, couplers and even the injector to head grommets to make sure all are seated well before pulling out too much fuel.

good luck!

dave
 

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Discussion Starter · #3 ·
thanks for the reply.... yeah the vac line is always hooked up, i have checked everything a number of times and there is no boost leaks, except for my boost guage line that keeps popping :WTF: ..... but i fix that everytime i see my boost guage stop working.
 

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desufnoC
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SupraDreamer44 said:
thanks for the reply.... yeah the vac line is always hooked up, i have checked everything a number of times and there is no boost leaks, except for my boost guage line that keeps popping :WTF: ..... but i fix that everytime i see my boost guage stop working.
Zip tie that vac hose that likes to come off, I had the same problem, the one on the drivers side on the back of the intake mani near the firewall.

Also, just to clarify, you want to set your base fuel pressure with the vac line off, and THEN put it back on when your done adjusting.
 

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Discussion Starter · #5 ·
myMUSICveins said:
Zip tie that vac hose that likes to come off, I had the same problem, the one on the drivers side on the back of the intake mani near the firewall.

Also, just to clarify, you want to set your base fuel pressure with the vac line off, and THEN put it back on when your done adjusting.

its the little plastic line that runs to the boost guage... it is not popping off it is just popping period, everytime i take the boost up real high it breaks and there is this little black hole.

I didn't know that you set fuel pressure with the line off.... thats good to know. So when i say i am running 40 psi base fuel pressure. i was really about 48 psi?
 

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LEADED FUEL ONLY
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You need ot stop driving the car and install a wideband.

You're tuning blind and you are going to be replacing this motor very soon.
 

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desufnoC
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SupraDreamer44 said:
its the little plastic line that runs to the boost guage... it is not popping off it is just popping period, everytime i take the boost up real high it breaks and there is this little black hole.

I didn't know that you set fuel pressure with the line off.... thats good to know. So when i say i am running 40 psi base fuel pressure. i was really about 48 psi?
Well, the vacuum in the intake mani can vary, so it wont always be 8psi, I don't think anyway. Probably differs from car to car.

But yes, you set BASE FP with vac line off. Thats what base means as far as I know.

Sounds like you have the FP up REALLY high. But listen to aljordan and hook that baby up to a WB.
 

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Discussion Starter · #8 ·
I know ...... I am just too poor to afford one, anyway I am trying to get it done, and should get it tuned properly by the end of this week, I just wanted some insight on what everyone else runs and what base fuel pressure actually does.
 

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desufnoC
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The most base FP I hear of people running is around 40-41, on 550's anyway. Suppose that would change with larger/smaller injectors. The higher the base FP, the overall richer the fuel mixture will be all across the RPM band. The less base, the leaner.

Think of it as a global rich/lean. Where adjusting with a SAFC or other fuel comp can add/subtract fuel in specified spots on the RPM band.
 
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