WTF? Is there any explanation for this or were you just jesting?

 

You know, ever since I've been on this forum I don't recall Gary ever jesting...

But there was some explanation. A golf ball is not smooth - it has indentations on the surface which actually make it go further. So the theory is that a slightly dirty car would also have the same effect. Gary is probably one of the few who would notice it - people who don't hypermile would probably not notice a difference.

 

Hi Alan

I never had an explanation as to why but I always knew washing and waxing never improved my MPG. Last November I was ask to hypermile the yet to be release new BMW X6 Active Hybrid. German Vox TV was doing a documentary on hypermiling and BMW was letting them do a review on this 480hp full Hybrid in Miami. This is a $103,000 vehicle so I had my '09 FEHL detailed in case they wanted to video my vehicle in the documentary also.

The wax job took its toll on my MPG and I was having a hard time trying to figure out why. Remember, I'm averaging 57mpg tanks so I get ~70mpg after warm-up on good routes and know when there is a problem. As my '09 FEH got dirty after the trip to Miami, I started seeing my MPG improve again.

It all came together shortly after when I saw Mythbusters on TV demonstrating MPG on a clean vehicle and the same Taurus with clay dimples like a golf ball. Mythbusters explained the effects of air behind a moving vehicle and I think it answered why I dropped my MPG in my FEH after having it waxed.

GaryG

 

Which moves thru water easier, a speed boat or a speedboat with a hydrofoil?



It's all about friction, the more surface in contact with water or air (both fluids), the more energy required to move it. Little bumps cause the airflow to jump over the surface, so less friction.

 

There is issue of speed. Does a "dirty" car at XX mph (pick your speed) require less horsepower (less fuel) to propell itself forward than a freshly detailed vehicle? Hmm, many of us have scanguages and can document this belief or misbelief via a digital camera/video.

 

Here's more info on surface smoothness vs. mileage: http://www.treehugger.com/files/2009...p-mpg-plus.php

 

The Mythbusters test was done professionally with more equipment and people.

I developed a new P&G strategy the month before having my '09 FEH detailed on 11/5/09, the day before the documentary. That month I increased my mileage to over 57mpg. Why not look at my mileage log before and after I had my FEH detailed for any change after. You can see the drop in MPG till the wax job went away.

10/27/09 - 57.742mpg tank average before waxing
11/12/09 - 54.748mpg after waxing
12/14/09 - 55.086mpg
01/22/10 - 57.263mpg
02/11/10 - 57.908mpg
03/08/10 - 57.655mpg
03/30/10 - 58.123mpg
04/28/10 - 57.615mpg
05/21/10 - 57.568mpg
http://www.cleanmpg.com/index.php?pa...9&viewcar=2612

You can't make this stuff up people, clearly something (I say the wax job) caused the drop in MPG after waxing on tank 11/12/09. You can see my mileage improving over the next month.

GaryG

 

You can make better mileage with more EV. I want to see a difference in HP. You can't dispute HP differences at the same speed.

 

That's great! Now get waxing!

GaryG

 

Your blaming the wax job but it would have be a very poor wax that's gone in a month! I'd be looking for some other reason for the drop if it were me.