This is how I understand it man.

If you had an adjustable FPR, you could MECHANICALLY trim or lean out the idle fuel pressure as much as possible to pull pressure off your new bigger injectors which still might not be enough. At low throttle and maybe still at idle, the adj FPR probably would not be adjustable enough to fine tune your fuel injectors so the ECU would be koscher and happy. That's where the S-AFC sould come in to adjust your fuel pressure to a very fine degree ELECTRONICALLY working in percentage increments to lower or raise 50% under or over the present mechanically adjusted fuel pressure.

With an Adj FPR, the S-AFC would have to make a LESS dramatic trim in fuel than with a non-adj one, but it still would have to trim.

With your non-adj FPR, you may still be able to theoretically use your present FMU riser. I don't know, though. It'll be a mathmatical question. Why? With a S-AFC, you can trim and lean out where necessary, so long as the level you need to trim to is within the 50% reduction of fuel pressure required to run your car properly. I'm guessing at idle, you're still relying on your stock FPR to spring-load the 235cc injectors to a fuel pressure at 47 psi so you'd need to tune that down to whatever fuel pressure that spring pushes the 440cc injectors to with a S-AFC. This will probably work. Under boost, your FMU riser is going to mechanically pressurize your fuel system to 12:1 parts fuel for every pound of boost it sees via the vacuum lines. That's way too much. Your S-AFC would need to fine tune that with whatever amount of fuel 440cc injectors push out for 12 parts of fuel to every part of boost. I don't know if it's over 50% of the S-AFC's capabilites but it sure might be.

This is a good time with some of that mathematical know-how to compute some of this in relation to 440cc fuel injectors....

Jason
98' Eagle Talon ESi-T
Mitsu Super 16g Turbo(HRC)


http://springfielddsm.homestead.com/JasonsPics.html

_____________________________________
Jason ESi-T

04' BMW 325Ci
91' Nissan 240SX
98' Eagle Talon ESi (sold)