I sprung a nasty leak from my SC on Fri... leaking from the seals/rings on the unit. I found a great new speed shop locally and he was willing to squeeze me in to reseal the SC.
While he was under there we added a 10:1 FMU. I cannot remember the name of who makes the unit. I think it was HKS or Vortech, I will ask him on Monday.
I feel like the VX goes into boost much smoother and has a tad more power when in boost. I also have noticed that my weird idle for a sec at startup in the mornings has vanished. Seems to feel over all smother. I am going to go get it dyno'd again soon to see if the curve when I am in boost has smoothed out and if it is running richer now as I was running a bit lean.
Over all I am very happy... so far with this mod, then again I have only got to drive it for a day.
Some photos of the unit, pardon my dirty azz engine, it is getting cleaned soon.
In a nutshell, the FMU adjusts fuel pressure when the boost comes on, regulating it at normal levels during normal operation and dramatically increasing it on demand. It is purely a mechanical device, using different sized disks inside the unit to alter the pressure at which the FMU takes effect. This makes it relatively easy to install and adjust.
FMU allows the car to run normally on a small injector, but can also increase the rail pressure under boost which, in turn, forces more fuel through the same size orifice. The fuel that the FMU adds has a direct relationship to the boost pressure.
The Pressure ratio determines how much the fuel pressure is increased per psi of boost pressure. A 12:1 FMU, for example, will increase fuel pressure by 12 psi per psi of boost. It is typically recommended that a 10:1 or 12:1 FMU be used in order to ensure that the A/F mix will not be lean.
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