2000integrals

OK, so another question, if i want to use my stock injectors and run boost, what is the highest psi i can run and still be running safe and secure (keep in mind it is my daily driver)? Also, if i keep the stock injectors for a little bit, can i still use the SAFC to control them? The only reason I want to use the stock injectors is because i am dying to put this damn kit on, and want to wait and save money to buy rc injectors.

Zeusfire69

You can use the SAFC or VAFC to add fuel with the stock injectors. They will not give you as much fuel as a 390 or 450cc injector and they will max out MUCH sooner, but you CAN use the SAFC to richen up your A/F ratio with the STOCK injectors. The whole point in trying to keep the stock injectors is that is it WAY easier to tune.

All the SAFC and VAFC do is change the signal going to the ECU from the MAP sensor, thus tricking it into adding or subtracting fuel. If you can keep enouph fuel going into the motor with the STOCK injectors when you are in boost it is acually safer than going to bigger injectors with the hack. The reason is that when you turn the big injectors WAY down the timing gets WAY advanced becuase you are confusing the computer. When the Map signal is all screwed up the computer advances the timing to try and compensate, and that can be just as dangerous, if not more dangerous than going lean. As long as you don't go lean, you are acually safer using the stock injectors.
You really do need a WIDEBAND to do this correctly, but if you want to take the chance, the cheap A/F gauge is better than nothing.

If you don't want to send alot on your setup, and you never intend to go higher boost, than the FMU is a better idea for you. If you alread have the SAFC, the best way to go would be to get the bigger injectors and the AFC hack, but remeber to LOWER your base timing, it will keep you safer this way. Look around, you can find 450's or 390's for pretty cheap. You just have to keep you eyes open, ----, I best there are some for sale from somebody on here...

2000integrals

thanks very much for all that info, that explained a lot to me, thing is, i now have more questions, i hope you dont mind me asking. 450cc injectors make my timing advance to an extreme, and the stock 240's or whatever they are might not be just enough, SO... would something in the middle be a better idea, like around 330 or so? Also, call me a noob if you want, but i understand the wideband would help lots in tuning, only thing is, i dont really understand what the wideband is telling me. It is measured on a scale of exhaust gas temp right? So how do i read that to tell me whether it is rich or lean? Is it the lower the temp the richer or something? Thanks for everyones help.

silverac

thanks for clearing that up but I say the hell with low boost.When I started my project I was told its addictive and they were not lieing.I say get a p75 and have projekteg hook you up with uberdata.turn boost up to 10-12lbs and kick v8 ***.if you have to save up do it cause itll be worth it .

Zeusfire69

AGREE!! beleive me, you WILL want more.

f22b1sedan

I am on 440cc injectors and the vafc and I have a base tune with no idle stumble and its making pretty good power...I intend to run 10psi on the vafc setup...and eventually be the "GINNY" for the megasquirt in my vehicle. Wideband is the way to go...I am going to get an onboard system eventually...and havent gone to the lengths of getting an AF guage...no need for a light show...especially since I will be getting the wideband

boosted_b16

if your going to run 5-7 psi and sont want to get to involved in it do your self a favor and leave the stock injectors in, put an fmu and missing link on it, and if you feel fiesty also put an afc on it and have it tuned... its a tone better to have a managment system... but dont be fooled i have seen a 255 pump, afc, fmu, and missing link on 15 psi making over 300 whp no problem, that ---- still gets the job done....

dragon

hold up. YOu've seen a car running the afc, fmu and missing link running 15 psi on stock injectors?