Balanced throttle at high RPM
I've got an RMS (Vortec) S/C on an OBD1 3.2L. I'm finding that the throttle response at high RPM is problematic. For instance, if I am accellerating at FT and then back-off a little at high RPM (above 5k) the engine reacts as if I suddenly lifted completely. The car reacts strongly (even a little violently). If I increase throttle a little, I get accelleration again, but when I lift (just a little) once more, I again get the whole car pitching forwards.
I'm thinking that the blow-off valve is opening completely and dumping all the boost. Shouldn't this be gradual though? I am working with MarkD to tune the car, but I'm thinking that this is not air/fuel, but rather the blow-off valve.
What do you think? If it is blow-off valve, any recommendations on replacement?
2002 540i M-Sport