Can A Car's Gas Mileage Be Improved By Adding Golf Ball Dimples?

It has been argued that dirty cars are more fuel efficient than clean ones for the same reason that dimples on a golf ball improve its aerodynamics during flight. The team at Mythbusters tested these hypotheses and found that a dirty car did NOT achieve improved gas mileage, BUT...

For a full-scale test, Adam and Jamie put a layer of clay on a car and did two more sets of runs on their track – one with a smooth clay surface, the other with dimples pressed into it. The respective fuel efficiencies were calculated as 26 and 29 miles per gallon. Although the original myth was invalid, the theory behind it was sound, leading to a final judgment of “Busted, Concept Plausible”.

Discussion threads on several auto forums discussing the Mythbusters episode note that "shark skin" textures on military fighter aircraft (and on America's Cup yachts) serve the same purpose, that dimpling on the undercarriage of some Lexus cars reduces noise (by reducing friction), and that textured paint is banned on professional race cars.

Mythbusters achieved the dimpled effect using modeling clay applied to the surface of a Ford Taurus. It's not clear whether the same effect could be achieved with a ball-peen hammer.

Screencap credit. A brief YouTube video of the car (not the full episode) is here.

Newest 5

Newest 5 Comments

I have had an overwhelming fascination of fluid dynamics that is anything related to termal, aero, hydro, etc.. One fo the most fascinating things that was how it was measured with "laser spectroscopy" for NASA. If this theory is true and the dimples work then there should be virtual prototyping for each specific case, either a car or a golf ball. Wiki mentioned that the number of golf ball dimples does vary, so some balls may have more dimples in specific geometric orientation. Where as the car had random orientation. Also regarding the car w/ dimples, the scale of the dimples came to question. When i had first considered this I envisioned dimples on the car similar in scale to a golf balls dimples. I have been pondering on this for some time. Immediately after finding out about computational fluid dynamics I realized the nearly endless disciplines the tests can be applied to. CFD is being used to study cardio-vascular systems. With a little bit of physics background it is entertaining to really change delta t and apply CFD to geology. I had also considered attempting to get a patent on the folf or disk golf long distance driver with dimples, unfortunately it had already been done although, I have seen or come across in research little results of testing. After further consideration and application of CFD to time trial race bicycles (I tested a few couldn't believe it I was like keeping up with traffic, super light frame, amazing construction, some places almost felt constricting) I focused on the golf club itself. Certainly you could change the shape of the shaft from round to delta and then possibly cover the entire club with dimples. I did see that some CFD testing has been completed on Long Distance Golf drivers. Not a surprise, giving the club an elongated delta shape increased performance. If the dimple thing is universal than these are some of the thing I envisioned as uses just of the top of my head, boat hulls (this area is a wealth of fluid dynamic study), so a boat hull with cfd dimples (again I am just speculating), hybrid baseball bat, semi truck trailers, helmets, race suits for olympians such as swimmers or down hill skiers, possibly a hybrid foot ball.