It is designed to be linear with manifold pressure. With manifold vacuum, it will be at the set pressure minus the manifold vacuum, and with boost it should be linear with boost. So if you have a 3 bar pressure regulator, at 1 bar of boost, you should have 4 bars of fuel pressure.
Thanks. I'm assuming then that it's still better to have a RRFPR attached to get better control over the fuel pressure. Is 1 bar boost like 14 psi? I think mine is set up for 70 psi for 7 psi boost. Someone called my RRFPR some ghetto hack crap, thus my question.
an old low volume nitrous trick for more fuel was to plumb the line into the vacuum side of the regulator, it would pretty much turn off the regulator and send full fuel pressure to the injectors. probably not the safest thing to do for the engine
