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

Argsh... Let's hammer Detroit!!

If you're creating the dimples by adding a layer of clay, then doesn't the dimpled car have less clay, weigh less, and hence use less gas?

@Geekman - the weight of the car didn't affect mileage at a constant speed (it might have an effect during acceleration or on upgrades). In any case, Mythbusters controlled for this by taking the clay removed in the dimpling process and putting it in the back seat of the car, so that the dimpled car weighed the same as the undimpled control.

Simpsons did it!

Ned: Whatcha diddely-doin', neighbor?
Homer: Aw, putting speed holes in my car. Makes it go faster.

My Ford Taurus was caught in a hailstorm a few years, creating several small dimples... you think those will help?

Based on an article I've read a while ago, I say this is to milk naive people out of their money. It compares golf balls to airplane wings and describes why dimples are not good for an airplane wing. Long story short, there's no perfect aerodynamic surface. It depends on object's shape. Have a look:

http://www.aerospaceweb.org/question/aerodynamics/q0215.shtml

A good hailstorm ought to fix it.

they mention something about it not working by just hammering dents in the metal before they started putting clay on the car. I don't remember exactly what they said but yea.

Minnesotastan - If the weight didn't affect mileage, they're doing it wrong. Weight lowers mileage because it flattens the tires, increasing drag (same for bearing drag).
They should have used a wind tunnel. But then, I'm sure the manufacturers have done that already.

A textured surface will have lower drag, and therefor, be more efficient, than a smooth surface, all else being equal. It would take some research to determine the right texture, but it could be done. However, most people seem to be forgetting that the myth was that a normal dirty car would get better MPG due to a dimple-like effect. The chances of normal dirt, dust, mud, and other road grime just happening to provide this effect are virtually non-existent. If the real world, the highly irregular pattern will add parasitic drag and lower fuel efficiency. Even if (or more likely, when) textured surfaces become common, dirt will affect MPG even more in the wrong direction.

Biker Ray-
They did the experiment over the course of one mile and the car was already up to speed at the start of that mile. Meaning that the long term affects of the extra weight were not part of the results. They even stated that the extra weight of the clay would, indeed, eventually cause a negative impact on fuel efficiency and that the cost of fuel to get the car up to speed were equally negative.

However, the point of the experiment was to see if the evenly dimpled surface would have a "golf ball-like affect" and decrease the drag and fuel consumption. Since metal doesn't easily form uniform dimples, they were forced to coat the car in clay and dimple the clay. All of the experiments were carried out on the same course and at the same speed, meaning that the per mile fuel consumption can be compared and a fairly accurate conclusion can be reached.

The reason golf balls have dimples is for control and for longer distance due to INTERACTION with the air.

Specifically, the dimples create drag due to a delayed separation layer, and hence less turbulence behind the ball. (some studies say the turbulence is made smaller, and is thus reduced.)

The reduction of turbulence adds to the distance traveled. (there are other control effects of dimples not relevant to the car application.)

The car only deals with separation at the rear of the roof and the rear of the trunk lid. The rest of the dimples are only causing pure drag.

I saw the episode last night. It was obvious the dimpled care got better fuel economy. So much so that car manufacturers should start making cars resemble golf balls.

It’s not clear whether the same effect could be achieved with a ball-peen hammer.

This is an experiment reserved for the recently divorced with a sports car.

I saw the Mythbusters golf ball car episode. Very cool. I think dimples may be the key to better MPGs, but there may be other ways to focus the benefit with not necessarily dimples but other indentions, or bumps and vallys on a cars surface. It is obvious that dimples boosted MPGs by 11%, what if we could get that number to 20% or 30% or more. To the the Wind-Tunnels!

Just so you know,(and don't try it yourself), I tried to sell a do-it-yourself gas mileage improvement/dimple kit a year ago on Minneapolis craigslist, auto section. $50 for a ball-peen hammer. I posted pictures of the golf ball and it's aerodynamics, and the choice tool, and of a hail damaged car. Yes I meant it as a joke, but someone must have thought I was serious, because the ad was flagged and removed within about 10 minutes.

Nice to know my hypothesis had merit though.

Boeing, Amtrak and all federal, state and local agencies should think about this for their fleets. I saw the Mythbusters episode and it was a clear difference. Airlines are doing everything they can to reduce fuel usage.

20 pct savings is a lot !!
i trust MythBusters more than the GOV..
Imaging the Repugs thinks the Public Option bad .
I thinks this should really be researched to save gas
and save the ENV..

Well, in all scientific tests we know that we don't know the result until we did it. In this case, mythbusters went out and did the test and proved that it works.

Maybe someone could wrap their car in a bubble wrap and try it out?

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.