why does it only whine under acceleration?

rik1083

I guess it has something to do with throttle position/calculated engine load and what position the bypass valve is in.. but can anyone explain it step by step?
I notice that under acceleration the manifold pressure is high, but when it reaches the speed for the throttle position, it goes low again..

winstar

rik1083 said:
I guess it has something to do with throttle position/calculated engine load and what position the bypass valve is in.. but can anyone explain it step by step?
I notice that under acceleration the manifold pressure is high, but when it reaches the speed for the throttle position, it goes low again..

I suspect that, if it's anything like turbos, the noise comes from the blades creating pressure waves. When the by-pass is open the blades are effectivly running in a vacume so no pressure waves being created.