SAN FRANCISCO - The Discovery Channel's science television show "MythBusters", which by its namesake sets out to bust common myths and urban legends, recently conducted several experiments to answer questions on fuel efficiency.
In an episode titled, "Clean Car vs. Dirty Car", the show's scientists set out to discover whether a dirty car runs as efficiently as a clean one. The scientists began by rigging a special gauge to a nondescript sedan, measuring fuel usage to the ounce. To get a uniformly dirty car, the MythBusters used a pressurized sprayer to coat the car in a specialized blend of dirt and water. The aerodynamic clean car did, in fact, appear to run more efficiently than the dirty version.
Completing the answer to that question, the scientists then proceed to expand the experiment to full scale by encapsulating the car with 750 lbs. of clay, then carving out about 300 golf "dimples", creating a golf ball-like surface. The expected fuel efficiency was based on the demonstrated aerodynamics of a dimpled golf ball. After proving golf balls with dimples traveled much farther than a plain ball of the same size with a smooth surface, the team wanted to see if the theory would also hold true with a vehicle.
To the amusement and disbelief of the scientists conducting the experiment, cutting out golf-sized holes in the clay exterior of the vehicle resulted in an 11-percent increase in fuel efficiency. Click here to see the car in action.