Re: Benefit of disconnecting vacuum hose from FPR? (queue)
i know its confusing, i was a t first.
this is the deal....
a 3 bar fuel pressure regulator, makes 3 bar of pressure in your fuel system ONLY when the intake manifold is at atmospheric pressure(WOT). when you are in vaccume(part throttle or idle), the fuel pressure gauge would read LESS than 3 bar. If you were in boost, it would read more than 3 bar.
basically how the fuel pressure reg works, is it makes sure there is always 3 bar of pressure difference between your manifold, and the atmosphere. since you can change you manifold pressure via the throttle, the regulator has to know that this is happening. thats why it has the vaccume port on it that should be hooked up. if you did not hook it up, you would run rich at idle, and lean at WOT.