cheap areo fix! (wash & wax your car)
 

one way to increase mpg is to wash your car and wax it. this will reduce air resistance thus increase mpgs!!!

Got any data to back that up?

Actually, I have read that several times before too.

BUT ...this comes from sources that apparently do not research the concept.

Sorry to tell you ... but it's myth.

I haven't seen you post before. Welcome to the forums !

HotRod magazine did a thing on aerodynamics at a windtunnel location, & the 'expert' that runs the windtunnel says a dirty car has the same drag as a clean car, it makes no difference

it doesn't say it here, this is the article, but the online articles tend to leave out stuff thats in the magazine

http://www.hotrod.com/techarticles/b...ips/index.html

It is true for a lear jet. A car does not go fast enough to make a difference.
The boundary layer on a car is thicker than the roughness of the dirt film.

alcivic -

I have head that this is true for airlines because they are able to save fuel doing this. I don't think it translates to cars because they don't travel fast enough. Didn't UPS have an ad where they were washing their big brown jets a long time ago?

Here is the only tangential example I could find :

Clean Drives Airline Fuel Efficiency - June 10, 2008
http://greentechnolog.com/2008/06/cl...fficiency.html
CarloSW2

I always believed the opposite.
A dirty car,(not filthy and covered in droppings) would get slightly better CdA.
Similar to the way dimples on a golf ball work.
Now somebody (not me, too lazy) is gonna hafta research.
Schultz.

Well I think Im just going just to leave well enough alone with my hood thats been rough and sun faded since I bought the car 5 years ago. :)

Speed of a golf ball:
http://findarticles.com/p/articles/m...4/ai_101967391
Faster than my driving. Tiger Woods gets up to 180 - 200.

That's the source that I was going to use.

Also, windshield angle steeper than 45 degrees is just for 'looks' It does nothing to improve the cars drag - ( that one really took me by surprise! )