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Old 11-19-2014, 04:13 AM   #11 (permalink)
RedDevil
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Quote:
Originally Posted by taco View Post
I don't know about the sides being open if that created bad turbulence. I was wondering if it would be better to block it all the way across or if it gets too hot, to block off the outer parts and leave a hole for the center.
I'd say block all except the sides vents...!
They are there by design, deliberately blocking the air flow.
Same principle as the protruding A pillars, between which the front window seems sunken as if set back too far. That too lowers drag, counterintuitively.

As I see it, if you cover them more air will flow along the sides instead of over the car, but the angle around the bumper is too sharp; it will cause extra drag.
The 'scoops' at the sides of the bumper create a high pressure area which pushes the air around the bumper more smoothly.
You want as much air flow over the car as possible. That's where the energy that was put in moving the air away can be gained back by the gentle curve of the roof. The sides don't do that.

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