maxim

I am a bit confused with all these posts of an FMU having 12:1? What is 12:1? Is an Apexi VAFC considered an FMU? I will probably get this(Apexi VAFC)before or when I get my turbo kit, just wanted to know if they were one in the same.

ArizonaTurbo

An FMU is a "Boost Dependant Fuel Pressure Regulator" ! The 12:1 explains it fuel to boost ratio; 12 psi of fuel pressure for every 1 psi of boost! An APEXi VAFC is only a piggy back air/fuel controller!

VTC_CiViC

The Apex'i V-AFC is simply a VTEC and fuel curve adjustment tool. It allows you to change your VTEC X-over and to fine tune your fuel delivery by adding or subtracting a little fuel at any given point in the rev range. The FMU on the other hand is a mechanical device that kind of piggybacks your FPR. By reading manifold pressure, the FMU can increase fuel pressure in the rail by however much it is calibrated to do. For example, a 12:1 FMU will increase your fuel pressure at the rail 12psi for every 1psi in manifold pressure it reads. An 8:1 FMU will increase fuel pressure 8psi for every 1 psi in manifold pressure it reads. Understand? It's a very simple yet effective way to have your fuel delivery increased in a somewhat linear fashion dictated directly by how much boost you're running. The V-AFC would be good to fine tune the specific RPM points you may want to lean our in richen just a bit, but the bulk of the work is done by the FMU.

maxim

Thanks guys, I get it now