I want to purchase a Vortech FMU because people have suggested it to me. Could somebody tell me how it works? Does it use boost to force fuel in, or does it allow more fuel in by opening a valve? Thanks a lot.

 

yes it uses boost to force fuel in some way. heres how it works. theres a vacumm line hooked to the fmu. when the vac turns to boost it spins a disk inside the fmu, the disk then forces the fuel so yea thats how it works.

 

It uses the boost pressure to restrict flow to the gas tank.

The higher the boost, the higher the restriction (more pressure).

The boost pressure pushes on a disc inside the FMU, the disc then pushes a pluger down block fuel flow to the gas tank.

The bigger the disc in the fmu the more pressure per psi of boost (12:1 is the largest disc, 4:1 is the smallest).

 

Thanks. Anybody else have anything to ad?

 

hrm...

if your idle fuel pressure is x, a 12:1 FMU will rise the fuel pressure 12 psi for every 1psi of boost...so at 6psi, your fuel pressure will be

x + (psi)12
or x + (6)12
or x + 72

for a 12:1 FMU..

does that make sense?

 

for a small turbo, such as the greddy kit for eg's (SOHC's), would you want 12:1 or 4:1?

 

depend on your injectors
stock one use 12:1