[RKDinOKC]

I am an amazing problem solver/troubleshooter, even if I say so myself.

Driving the 928 I noticed a wind noise/whistle that started at about 40mph and went away at 50mph. When checking the oil I noticed a screw missing.

On the 928 the area in front of the radiator is sealed from the engine compartment. There is a trim piece a couple of inches tall on the top of the radiator that has a rubber seal that seals against the hood. One either side in that trim piece is the cold air intakes. Between the two intakes are two 1/4 inch screws that hold the trim pieces and radiator together. With one of the screws missing it all seemed snug enough, but it left a 1/4 inch hole.

Replaced the missing screw and no whistle.

The pressure differential between the front of the radiator and the engine bay is just right to flow enough air thru that screw hole to whistle when going between 40 and 50 mph.

It also tells me the design is not just a cold air intake but a ram air intake as well.