Originally Posted by J08M3
That BMW didn't leave big enough inlets for the M3 to get enough air up to 8,400 RPM. In this particular instance it just sounds a bit odd to me.
Yep...the main/largest source of air is the lower inlet, the one where the driver's side foglight would be. That location, with it's much straighter pathway to the airbox and it's location of a very high pressure area, would be more than sufficient for most motors. The radiator inlet, very restricted in size and bends, and the top hood inlet are, in essence, a very cold-air intake.
And I'm sure there is sufficient air for the motor.
My thoughts are that the "ram-effect" that is so prevalent on high performance cars, bikes, etc....could be improved with the flapper.
It would ram when it could and open if the motor needed it. So you'd get, in theory, the 1-2mpg increase that the other closed-box cars enjoy....and a pressurized intake.
Do you think the string colapsed on the mesh as a result of the air, that was passing over the hood at a high speed/pressure, because it was just "blown-over"...or does the vent actually enjoy a high-enough pressure from air passing over the vent that it becomes a legitimate intake source?
Or that the motor actually needs the vent as a source of air and creates a vacuum in the box?
A pressure sensor...even a decent boost gauge...would be able to show if there was positive or low pressure in the box.
Yet another thing I need to do.....