hey guys,
i plan to boost 7 lbs w/ a garret t3/t4 turbo on my gsr. my original plan for fuel managment was to use the VAFC i already have, some 450cc injectors, and a walbro fuel pump. then get it tuned. but today i talked to a guy at ATP turbo, and he said it wont be reliable. he told me i should either keep vafc, use stock injectors (because stock injectors will be easier to tune), and a better fuel pump w/ an fmu. and use the vafc to fine tune it. or.. get bigger injectors, get hondata and a better fuel pump. what do you guys think is a good set up for 7 lbs? and do i need a fuel pressure regulator?
thanks,
Jon

 

That's weird, you don't need an FMU since youf Vafc hack (vafc+larger injectors) replaces it. Typically, for applications from 7-10 psi, 450cc injectors are good with the vafc or safc. Honestly, I think your original setup was right. I don't know why the other guy said that. That walbro 255lph-HP In-Tank should works fine because you're running low boost. I did my homework and that's setup of yours is what everyone reccommended for a low budget style.

 

thanks man. thats what i thought too. but ATP turbo is supposed to have a good reputation in dyno tuning. im confused! haha. anyone else have any input?

 

I don't like the FMU setup at all. Bumping your fuel pressure is not a very precise adjustment, because fuel pumps and injectors do not increase their flow at a linear rate as fuel pressure goes up.

The VAFC hack will provide slightly better driveability but it's not really the ideal solution since it's still trying to work around the stock ECU.

You can get a Hondata s100 with boost option for a total price of $445 and then tuned on a dyno. The V-AFC is going to need to be tuned on a dyno anyway so that's an equal expenditure there, and you can sell the V-AFC to recoup some of the cost of the Hondata.

 

does anybody here have any sucessful set ups using a VAFC? if so, what was the set up? i really dont want to go through the trouble of removing the vafc and selling it n then getting hondata.

 

Ok, looking at this objectively. I don't see how you using the AFC hack with bigger injectors, is any less reliable than FMU with AFC.

I just don't think your guy is making any damn sense there....

In CA, I like these guys: RaVer Motorsports 559-733-4711

I wanna say they are in pomona, but I am probably wrong, give em a call, they have some sharp people there.
-PHiZ

 

alright, thanks man.

 

Generally speaking with the VAFC you dial it back to about -40% fuel trim across the rpm range and then use a dyno to fine tune it. It works reasonably well, but as I already mentioned it's not as versatile as actually reprogramming the stock ECU (which is essentially what a Hondata does).

 

-40% across the rpm range when you have 450cc injectors right? but isnt that only when you have the larger injectors with the stock motor. when i put the turbo in, shouldnt i have a little bit more fuel than stock just to keep it safe before actually tuning it?

 

by the way, can somebody explain to me what the settings mean on the apexi vafc?
1. wide thr
2. narr. thr
4. V/T unmt
5. TH- point
6. NE-P:Hvt
7. NE-P:Hvt

number 3 is the vtec point setting. thats all i know. haha. i know all those other settings have to do w/ fuel but why are there so many different settings? i had a fields sfc and it only had one thing for fuel settings in 8 points.