Help with fuel delivery

[coolsi]

What would be the best FMU (cartech, vortech, JR)and FPR for a civic si equipped with the greddy turbo? Also would these items be better than using the piggy back system that comes with the kit? Oh yeah I also have a V-AFC ready to go also.

[JRCivic]

Welcome to the board.
The question you ask is hard to answer: I do not believe the term "Better" is applicable... using a rising rate regulator like a Cartech or Vortech is simply DIFFERENT. Obviously, you can tune mechanical components manually on the dyno whereas the system that comes with the Greddy kit is NOT adjustable by the user... you have to be happy with what they have created for you. The good news is that the Greddy kit is well engineered and should give you plenty of trouble-free use.

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'93 Civic Si H/B with B18C1, JRSC @ 8psi
Best 1320: 12.68 at 110 mph

[coolsi]

Thanks for the welcome! Oh I see. Ok can somone tell me at what ratio they operate at? I believe the Vortech FMU is a 8:1 ratio and I heard the Cartech is an 1:1. For a turbocharged engine which ratio would be better? I also heard more pressure less the flow out of fuel pump. Is this correct?

[JRSCGSR]

Actually, the Cartech has an adjustable rise rate, so you can set it up to whatever size injectors you're running. I don't believe that there is a better ratio, it all depends on what components you have in your system. I believe DRAG kits come with a 12:1 Vortech FMU, but that is for use with the stock fuel injectors. If you upgrade the injectors to 440cc for example, you're definitely not going to need a 12:1 rise rate, cuz your car will be running too rich. You really have to figure out the correct rise rate for your specific system(fuel pressure, fuel injectors) and application(turbo, s/c). Your statement about more pressure equaling less flow applies to the stock Honda pump only as far as I know. Doug from hondata did the test and found that to be true. Most of us here have a high flow fuel pump that does not flow less at more pressure(up till a point that is).

Jon

[JRCivic]

Actually, all pumps flow LESS volume at HIGHER pressures...

The good news is that pumps like the GSS-342 still flow far more fuel than is necessary for the typical 300 crank HP car up to about 100 psi of fuel pressure.



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'93 Civic Si H/B with B18C1, JRSC @ 8psi
Best 1320: 12.68 at 110 mph