Originally Posted by
Donkeyface
No it doesn't seem to do it unless the car is being driven on the road or when the engine is started from cold, perhaps the throttle isn't open enough unless the car is accelerating.
So you've checked the pulleys, and performed the power braking procedure? No drivability problem other than the "whirring" noise? Have you checked all the air intake connections? Does the noise go away after it comes up to operating temp.? Maybe slight exhaust leak that goes away when it expands after heating up? Maybe we could hear a recording of it? Just a guessing game here now.