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Old 12-04-2008, 04:58 AM   #18 (permalink)
ChrstphrR
EcoModding Apprentice
 
Join Date: Jul 2008
Location: Sault Ste Marie, ON, Canada
Posts: 128

Schwartzejetta - '00 Volkswagen Jetta TDI GL
90 day: 52.87 mpg (US)
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Quote:
Originally Posted by Cd View Post
As far as dimples on automobiles, I notice that Lexus did a famous job of dimpling the LS430 underside, and to my surprise VW is still using dimpling on the undersides of their cars . There must be something to it, otherwise they wouldn't bother ( Lexus used the dimples as a PR stunt, and this may have been the actual reasoning behing the dimples, but why then is VW using them if they don't really work ? )
Dimpled underpans would have another non-aero reason for being dimpled...
NVH reduction - Noise, Vibration, and Harshness.

Especially for metal parts, dimpling, ribbing, and other forms of bracing or mass-damping would keep an otherwise perfectly flat panel from vibrating at higher frequencies.

High frequency vibration are more likely to bother occupants inside the car, than lower ones. As an overall structure, a more rigid car has better handling, to boot.

That's just my take on that idea. It may be good PR, may possibly have some benefit for delaying flow separation, but my best guess is it's a compromise of all three.
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Current mod: Skidplate/Undertray for my MkIV Jetta. Next mod: CAD drawing for skidplate so other Jetta/Golf drivers can make one too!
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