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Old 08-26-2009, 11:37 PM   #6 (permalink)
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Camryaro - '92 Toyota Camry LE V6
90 day: 31.12 mpg (US)

Red - '00 Honda Insight

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Originally Posted by MetroMPG View Post
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.
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.
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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