I use a car wax (3M Perfect-It) that feels very very slick to the touch. I mean, my hand sometimes slips off when I go to close the hatchback or a door. I was just wondering if anyone has ever heard of something like this improving fuel mileage. Just curious. I haven't even gone through a tank of gas in my Prius yet and don't have any way to do a before-and-after comparison.
No, not really. You have to maintain a laminar flow for that to make any difference. The normal surface on the Prius is smooth enough for the flow. Tom
so you would have to cover the car with a rolling surface.. like huge delivery belts (but flush).. or some magical moving liquid that moves with the wind? that would be cool... An outer shell that actually moves or propels would be pretty awesome
Thanks. I figured as much. If it did, the manufacturers would be touting the fuel saving qualities of their wax. So, I guess I shouldn't worry about the fuel-robbing potential of adding a clear bra (which is a little rubbery and non-slick) to the front bumper, hood and fenders.
when i google for 3m perfect fit, all i get are pages for the rubbing compound, and that is something you want to use very sparingly..
I think you hit on a million dollar idea - you start selling the wax and claim it will give you better MPG. You might try selling it as a supplement like those "products" that claim to lengthen the size of a man's you-know-what to avoid jail time...
I read a study a long time ago that reported a clean, waxed car does improve gas mileage, but only minimally - such as 1 - 2 mpg, as does rolling up the windows. Laminar flow is best but difficult to achieve due to all the components that add parasitic drag such as the door handles, bumpers, radio antenna, muffler, etc. The obvious largest factor that affects gas mileage is your tire pressure. Under-inflated tires will rob your performance by as much as 5-10mpg! And there are other disadvanteges such as radically increased wear and danger to premature failure due to the excessive amount of heat generated.
This is car wax that has no cleaning compound in it at all. It is hard to find but it is by far the best I've ever used. So easy to apply (just rub on a thin coat with a damp cloth) and nearly as easy to rub off. It shines so well you won't believe it and, like I said, it is super slick to the touch. My friends and neighbors comment on it so much we actually hosted a car wash and wax and BBQ at our place last spring. It lasts a long time too. About every 2 or 3 years I apply it to the painted surfaces under the hood and in the door jambs. Then you can just wipe them clean with a damp rag. Great stuff.
Odd that they didn't include the most aerodynamic production vehicle ever - the EV1. Well, yes, actually. As long as you aren't looking for what I'd call *significant* savings. But I'll tell you what - the EV1 paint was specifically manufactured and applied to be as smooth as possible purely for aerodynamic advantage. I believe the car had six fine coats of paint. Honestly, you've never seen a better production paint job than what the EV1's came with. Smoothest and most durable paint I've ever experienced.
By significant I mean measurable. The boundary layer flow on any production car will be the same with the smooth factory paint job or with some slippery coating. The shape of automobiles is just not aerodynamic enough for a coating to make any measurable difference. Even cars with good aerodynamics have a big layer of detached air at the boundary. You could possibly make a measurable difference with active boundary layer control, where thousands of tiny holes are used to suck away the turbulent boundary layer. It works on jet aircraft, but I imagine the power to do it would overshadow any gain on an automobile. Tom
One last post. I think I discovered why the slippery "Perfect-It" wax is so hard to find. It looks like 3M stopped making it. But they make a replacement that, as far as I can see, is the same stuff. It is called "3M Performance Finish." I just got a bottle of it at Wally World and it appears to be exactly the same but with a different name and in a different bottle.
