Waxed car = Higher MPG?

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1,251
Location
Austin, TX
A coworker of mine claims that he gets better MPGs after waxing the car. While this is reasonable it seems to me that the difference is most likely too little to tell. Anyone?
 
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By Detroit
I noticed I walk about 0.02 mph faster in tennis shoes than I do in hiking boots. (Sorry, couldn't help it [LOL!] ) This could explain the poor mileage I have been getting in the past couple years. Not that I ever waxed my truck, but that I never wash it, so as the dirt layer builds up the roughness coefficient increases and the mpg goes down. [Razz] I think any increase in mileage from waxing would be negligible unless maybe he is doing 100+ mph. I wonder if your co-worker also happens to do other maintenance the same day he waxes, like pumping up the tires. [I dont know]
 

Jonny Z

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Austin, TX
I am sure his tires are always on spec +/- .1 PSI. Being an engineer and a car geek, his vehicles are ALWAYS in tip top shape. I really don't buy the wax MPG thing. I wax so the bugs wash off easier. [Wink]
 
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Western Washington
I've read on various sites that airlines wax their planes really well to improve fuel economy. Of course, those speeds and aerodynamics are a whole different ballgame compared to cars.
 
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Location
'Stralia
I think it's the other way 'round. A golf ball has dimples to affect the boundary layer (http://en.wikipedia.org/wiki/Golf_balls), and provide less drag. Once read what I suspect to be an urban myth that a NASCAR driver drove with a vynil roof to increase top speed. That being said, polishing the stationary blades on an impulse steam turbine has a startling effect on efficiency.
 

ALS

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1,862
Location
Pittsburgh
Like Pablo said over 50 or 60 mph it would help some. It may give you a .001 percent increase in gas mileage. I've read that a CLEAN car gets better mileage. Again back to less wind resistance as the air passes over a clean smooth surface. Shannon: Once read what I suspect to be an urban myth that a NASCAR driver drove with a vinyl roof to increase top speed. Yes that is true since the rough surface of the vinyl roof cause turbulence in the air passing over roof and the rear the car. Thus less drag from the back of the car due to a vortex generator effect on the rear of the car and less lift from the smooth roof. The cars used during the 60's 70's and 80's would benefit from this addition with their boxy body styles. With the new style of body created for aerodynamics makes this addition to a car today inefficient as far as fuel economy goes due to the increase in drag it causes.
 
As I heard it, one NASCAR driver tested a vinyl roof in the late 1960s when they first became a common sight on American cars. At 150+ mph the stupid thing peeled right off the sheetmetal, so NASCAR banned them as a safety issue.
 
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404
Location
The Mid South
Roger Penske did the vinyl roof thing with the 70's Can-Am Camaros, driven by Mark Donahue. He had pinholed the vinyl, which allowed for air bleed into the low pressure area behind the rear window, giving less aero drag. The idea worked well, but they got him on it (and made him remove it) because it wasn't on the homologation paperwork. Curses, foiled again.
 
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Saskatchewan
quote:
Originally posted by Shannow: I think it's the other way 'round. A golf ball has dimples to affect the boundary layer (http://en.wikipedia.org/wiki/Golf_balls), and provide less drag.
Dimples or surface roughness could reduce pressure drag if there's enough flow separation, but they can also increase drag due to surface friction. So it would depend on body style, but I'm guessing that most modern car designs would not benefit from a rough body surface. Maybe vans and hatchbacks could benefit from some dimples right before the rear hatch? I'm also guessing that waxing would not make a measurable difference in fuel economy. I'm waiting for the wind-tunnel results before I'll believe it. [Smile]
 
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Location
stanwood, wash.
Richard Petty tryed the Vinyl roof thing around 69-70 and it peeled off badly. Plymouth Superbird if my memory serves me right, I remember seeing the pictures in the car magazines of the damaged vinyl. It was not a "urban myth", they did use them in Nascar.
 
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1,420
Location
Balto.
quote:
Originally posted by Jonny Z: A coworker of mine claims that he gets better MPGs after waxing the car. While this is reasonable it seems to me that the difference is most likely too little to tell. Anyone?
Tell your coworker to wax his car in better ventilation, I think the fumes are getting to him. [LOL!] The difference would be sooooo small at normal speeds that it couldn't be reliably measured. [Duh!]
 

blupupher

Site Donor 2021
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Katy, Republic of Texas
I had heard this also, but it was in reference to semi trucks. The truck with the freshest wax job (sometimes paid for by the other truckers) would get at the front of a convoy to break up the air.
 
Rain x allows rain to roll off the windsheild .Wax might help air rolloff a painted/glass surface creating less drag.Mph.,windspeed are also factors here.Your friend might be right on this.Every little bit helps
 
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1,979
Location
Houston
quote:
Originally posted by blupupher: I had heard this also, but it was in reference to semi trucks. The truck with the freshest wax job (sometimes paid for by the other truckers) would get at the front of a convoy to break up the air.
yeah, and catch all the bugs and cops' radar.....sounds likely truckerlore to me. If wax helps, it's certainly not measureable by the means available to the car driver, and if he "can feel it", he's dreaming.
 
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