S15 injectors and SAFC-2

[drifter808]

hey everyone,
I just recently put in S15 injectors in my redtop. i leaned out the safc to -22%. the car runs normal but it tends to really bog out on me sometimes. when im reaching peak boost in every other gear but first it will kind of bog out and not rev smoothly. for example when im in 5th gear and i floor it, the car will start making boost then when it gets to 10psi(peak is 12) it will just hesistate and lose power so i just stop right there. the only resaon im running the injectors is i already lost one SR to detonation and i dont want to lose another. Do you think my safc needs to be leaned out and tuned more? if anyone is running this similar setup could you help me out. Thanks Derek

[sunnys14]

do u have a wideband? if not then get one and check your AFR's to see if you are running too rich.

another thing to check for are leaking fuel injector o-rings. i had a leaking one and it made me run extremely rich and bog out.

[drifter808]

no i dont have a wideband. im probably just running to rich. im gonna try and sell some things so i can get it dynoed and tuned this week.

[boosteds13]

How did you arrive at -22% correction?

[sunnys14]

s15 480cc are bigger than s13 370cc by 23%

[drifter808]

i actually just went and checked cause i thought -22 didn't sound right when i posted. i got it set to -25. i used this guys method http://www.ka-t.org/forums/viewtopic...=safc+ultamate

[boosteds13]

Yes, I understand that, but that doesn't hold true across the board. You can't set your idle correction at -23% because you need to compensate for the injector dead time. Also, when you start going past -15% on the safc, it starts to wreak havoc on your timing. You end up getting too much timing advance in the upper RPMs and that's when detonation occurs and motors go bye-bye.

[drifter808]

ahh crap! it looks like i'll put in my old injectors and wait till i get it dyno tuned.thanks for warning me cause i probably could of lost another engine. i never knew that going that much could mess up your timing.

[boosteds13]

Originally Posted by drifter808

ahh crap! it looks like i'll put in my old injectors and wait till i get it dyno tuned.thanks for warning me cause i probably could of lost another engine. i never knew that going that much could mess up your timing.

Yeah, the whole principle behind the SAFC is to trick the ECU into thinking lower amounts of air are entering the motor, therefore adding less fuel. Thing is, the ecu adds more timing for less airflow and starts to pull timing as airflow and load increase. Don't get me wrong, the SAFC works great for fine tuning, say if you got a base rom for your injector size and MAF. You can make small changes to get your A/F ratio on the mark, but leanging out too much on it just leads to problems.

[drifter808]

well i talked to some of my friends and they said the safc wont mess with the timing. these guys are running 550cc and Z32 mafs. they said it's just alittle rich. anyone else have any insight on this.

[boosteds13]

Originally Posted by drifter808

well i talked to some of my friends and they said the safc wont mess with the timing. these guys are running 550cc and Z32 mafs. they said it's just alittle rich. anyone else have any insight on this.

good luck with your setup

[drifter808]

yeah im just gonna tune my engine with that. the guys i talked to drift in D1 so i can trust them.