View Full Version : can i run fuel management without the turbo 4 now

12-07-2002, 02:14 PM
can i run all the fuel management that i would use for my turbo before the turbo is even put in??
ie, Bigger injectors, walbro 225 fuel pump, and a fuel pressure regulator, with the Apexi S-AFC???
if i can, what will i have to set the safc to???
what are the pros and cons to doing this?
i wont be running it for long... im just gonna run it before i put in the rest of my turbo...cuz i wanted to get the fuel out of the way first... http://forums.freshalloy.com/ubbthreads/images/icons/confused.gif

12-07-2002, 03:02 PM
Yes, you can.

What you set the S-AFC to depends on what size injectors you're running.

If you're running 370cc/min injectors, you should set the S-AFC to -27% at every point, and that should get you close enough that it'll drive "ok".

Downsides are likely to be worse driveability, worse gas mileage, worse emissions, etc.


12-07-2002, 03:52 PM
well i plan on getting my SAFC first out of all of the... what about if i run my stock 270 cc injectors withe the SAFC?

12-07-2002, 03:55 PM
</font><blockquote><font class="small[/img]In reply to:</font><hr />
what about if i run my stock 270 cc injectors withe the SAFC?


Then you don't have to do anything. The S-AFC doesn't change things unless you tell it to change things.


12-07-2002, 04:49 PM
ok cool thanks for the help...i just needed to ask this question because i wanted to get all the fuel stuff out of the way before i start boltin on my custom setup...


12-07-2002, 08:00 PM
what else can you do with the safc can you run big injectors like 720's whats the diffrence between using the safc and having your ecu remapped

12-07-2002, 08:42 PM
The S-AFC has a +/- 50% correction. Thus with a stock ECU, on a KA24DE, you could theoretically run 540cc/min injectors; on an SR20DET you could theoretically run 720cc/min injectors. However, in practice the non-linearity of injectors at low pulsewidths limits you to much smaller injectors; Scott (Enthalpy) had 550's on his SR with just an S-AFC for a while, and it basically maxed out the tuning range.

The biggest difference between using the S-AFC and getting a remapped ECU is the timing. Not only can the S-AFC not alter the timing, but because it's just "tricking" the ECU, the timing that the ECU uses will be wrong for the load that the engine is seeing.

My personal opinion is that the S-AFC can be a useful tool for fine-tuning, but shouldn't be used for drastic changes.

As for what else the S-AFC can do...RTFM. The manual is available on the A'pex-i website.


12-07-2002, 09:05 PM

You believe that running a JWT ecu on MSD 72# injectors is a good idea, as well as using the S-AFC with the setup to fine tune is a decent method. No?


12-07-2002, 10:06 PM
Dave, that's basically my view. Start with something close to what you want, and then tweak with the S-AFC.


12-08-2002, 03:02 AM
ok this is my setup for turbo also..
all for 9-13 PSI
-Apexi S-afc
-550cc injectors (top fed with top feed fuel rail)
(anyone know where is can get top feed rails that are easy to install?)
-fuel pressure regulator (not rising rate)
-walbro 225 fuel pump
is that ok for the S-AFC??? am i missing anything?? will that be good enough for a T3?? does it sound like a good fuel system plan?
thanks for any help..

12-08-2002, 11:54 AM
Unstable Hybrids has top-feed fuel rail for the KA24DE for much less than JWT.

12-08-2002, 12:12 PM
cool thanks for the info i was planning on doing that with the ecu retuned and the safc but wanted to ask if i could get away without the jwt ecu no use in spending money if its not gonna make a diffrence thanks