At low RPM and 1/4 throttle I keep hearing a whirling/air buffeting noise from the passanger side of the engine compartment. It goes away after my vacuum gauge starts reading 0. It sounds like it corresponds with spool up, but its weird it only occurs at those particular engine speeds. Doesn't sound like a normal spool up to me. Car runs great otherwise, 10 PSI and no noise after 0 PSI.