Just wondering....

The stock FPR goes to about 43psi when there is no vaccum (WOT). How does a FMU then force a high fuel pressure when its sees boost?

 

It is quite simple actually.
If you take it apart, there is a rubber diaphagm that pushes onto a piston, which pushes onto a metal diaphragm. As boost builds it pushes into the rubber thus increasing the pressure on the metal diaphragm. The fuel enters through a port normal in direction to the metal diaphragm. A pressure balance is established between the diaphram and the fuel, so, obviously, as boost pressure builds, metal diaphagm pressure, and hence fuel pressure, increase. By changing the contact area of the rubber diaphragm on the piston, (switching discs), we can adjust the fuel/boost ratio.

 

Thanks guys! Kinda what I figured, but without taking mine apart (yet), I wasn't 100% sure.

 

I wouldn't take the FMU apart, it says so by Vortech in the installation instructions........

 

pish posh, i took mine apart, still works the same.