Re: Wind Deflector on a sedan (archive)

The E46 design seems very sensitive to wind noise, either from an open window or the moon roof. Maybe because the car is so well-sealed? Anyway, I believe the stock pop-up wind deflector is there for an interesting reason: to create turbulent air flow. Check it out: at low speeds if you you pull down on the deflector the wind noise is less, but if you pull down on it at higher speeds you get an unbelievable "wind tunnel" sound, due to some sort of strange resonance. By forcing the air flow to be more turbulent (via the notches in the wind deflector), this effect is reduced or eliminated. It's really quite strange--I've never encountered this before in any car.
So it isn't surprising you are getting funky noises if the stock wind deflector (the "turbulance-maker") has been defeated with the aftermarket deflector. If this is a BMW accessory, then I would say they have conflicting designs. If someone else makes it, then BMW should get on their case!

: Hi! I installed the oem wind deflector this afternoon to cure some of those wind noise when the moonroof if fully retracted, well the wind noise was gone but it was replaced by a deafening sound, does anyone with the wind deflector installed have the same problem? It goes away when you open one of the window slightly open, is it really designed to do this?

: Jeff
: Y2k 328i

Follow Ups:

Wind Deflector on a sedan JeffW 00:29 5/01/2000 (0)

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