Read the darn article yourself from this link:http://mythbustersresults.com/dirty-vs-clean-car


Adam and Jamie covered a car in dirt and mud and drove it down a track at highway speeds to measure its fuel efficiency, and repeated the test after the car was cleaned. They discovered that the average gas mileage for the dirty car was 24 miles per gallon while the clean car performed better at 26 miles per gallon. No kidding.


Now the rest of the article deals with placing a layer of clay on the surface of the vehicle.:"

They then tested the reasoning behind the myth, and tested how well dimpled golf ***** performed against smooth *****. They discovered that dimpled golf ***** could fly almost twice as far as smooth *****. Dimpled ***** disrupt the air around them, creating a smaller wake behind them and reducing drag. 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”.

The smooth clay layer produced the same results as a clean car. When the clay was layer was "worked" so dimples existed, the mileage improved. Does a dirty car have golf dimples? Note the error in the title.

 

Thanks for posting this. It is hard to believe anyone would think the opposite was correct.

 

See the new thread about drag reducing technology that has a location in Miami, Fl.

 

I've found out over the years, that dirt will preserve the paint quality also.

One of the things that deteriorates the car's finish most is sunlight.

I hypothesize that some amount of dust & dirt acts as sunblock, and prevents the harmfull rays of the sun from working on the paint job.

I've got a 1988 Dodge Truck that has never been garaged, and rarely washed, and the paint, overall, is in good to excellent condition. There are a few spots where the clear coat has peeled and then deterioration occurs more rapidly. The truck spent 5 years in So. Cailf and the past 18 in Colorado where the UV is stronger at the higher elevation.

 

Define "paint quality". You certainly can't be referring to lack of swirls, scratches and/or water/insect/bird dropping etching.

 

That's not how I treat my vehicles. I wax twice a year and the forward facing parts (grill, mirrors) get a second coat to make removing bugs easier.

 

I thought once that somebody tossed firecrackers on the hood of my truck but later found out that it was just bird droppings! Actually looked like burn marks.

 

Mine's been real popular with the birds at work....

 

They wash air planes for a Reason. A 747 after a good wash job gets 2 to 3 percent better fuel economy, Thats a lot of fuel for a 747.

 

Perhaps you could get them to fly in formation and "drop" in a golf ball dimple-like pattern.