Quote:
Originally Posted by MetroMPG
BMW is also claiming a 0.26 drag coefficient for this car through subtle aero tweaks:
- lowered ride height
- more aero friendly wheels
... and probably a few other things that aren't mentioned in the official press release I've seen.
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This is cool! It sounds like a bunch of small diffusers in the front directing air through the wheel wells so flow doesn't separate there.
Quote:
Air curtain
The big aerodynamic step forward for the 2011 3-series is the ‘Air Curtain’. This uses narrow, upright intakes in the lower bumper which channel air through the bumper and out of a slot inside the front of the wheel well.
As it exits the wheel well, this high-speed airflow runs across the face of the wheel, creating what is in effect a ‘curtain’ over the wheel face.
Smoothing the turbulent flow across this part of the car helps reduce the Cd of a 5-series from 0.28 to 0.27.
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