Dimpled Taurus from 26 mpg to 29.7 mpg.

[ausias]

HowStuffWorks Videos "MythBusters: Dimpled Car MiniMyth"

VEry impressive. I've seen dimples in underbody of Volkswagen AG cars and toyota Prius but never a full car. I read here that a Nascar could get +10 mph top speed after wind tunnel tests!!!

[Rokeby]

Lots of postings on this back in Nov '09.

Exec summary: Validity uncertain due questions about consistency across all test runs: air temps/density, engine/rotating parts warmup...

Mythbusters "tests" efficiency of dimples vs. smooth, and clean vs. muddy car

Mythbusters tests "golf ball" dimples

[aerohead]

Originally Posted by ausias

HowStuffWorks Videos "MythBusters: Dimpled Car MiniMyth"

VEry impressive. I've seen dimples in underbody of Volkswagen AG cars and toyota Prius but never a full car. I read here that a Nascar could get +10 mph top speed after wind tunnel tests!!!

If you've watched NASCAR you may have noticed that those cars have no bellypan whatsoever.
It makes sense that a bellypan would add 10-mph,however production dimpling,I believe has more to do with 'Noise/vibration/harshness' issues than aerodynamics.
These are sandwiched panels with acoustic liners.The spot-welds have got to go somewhere.

[Clev]

Mythbusters? Last time I saw them do a side-by-side fuel economy test, they did it by driving two Ford Explorers around a tight circular track until one ran out of gas. Not the most scientific bunch.

[ausias]

Cheap Dimpled aerofriendly polyetilene plastic or Drainage Layer

I found very cheap polyetilene for dimpled surfaces.