Outside of driving my 18 gallon tank until it was running on fumes (and nearly running out of gas), this wasn't much of an adventure.
Originally (on July 13th) I purchased 16.561 gallons of gas and had gone 409.0 miles on that tankful. (also, I paid 4.289 a gallon, ouch!). This translates in to 24.69657 miles per gallon.
Then I washed my car - and to be fair I did wash and wax the car in an automatic car wash. But I think that shouldn't make a difference...
This morning (August 5th) I purchased 18.298 gallons of gas and had gone 430.4 miles on the tank. (also, paid 4.099 a gallon, so it's gone down). This translates into 23.52169.
Wow, so that was a miserable failure. I didn't notice any perceptible difference in the way or amount I drove. I don't use my air conditioning all that often, even when it is warm enough, because I like driving with my windows down.
Anybody else want to give it a shot? Otherwise I'll call this a bunch of bullcrap...
It's actually better for your gas mileage to drive with the windows up because it makes your car more aerodynamic. So driving with the A/C on is better for your gas mileage than driving with windows down. That could be your problem.
But really, I think I'm with your evaluation of the claim.
Posted by: bleaus at August 5, 2008 09:46 PMThe AC versus windows down debate is weird. People differ. The last report I read said that > 45 mph, AC is more efficient.
Posted by: babada at August 6, 2008 07:44 AMThe AC versus windows down debate is weird. People differ. The last report I read said that over 45 mph, AC is more efficient. Under 45 mph, windows were more efficient. For exactly 45 mph, flip a coin every Tuesday until you get heads. If the number of times you flip is prime, your car will perform better.
First comment broke because of the less than symbol. Makes me a little curious about malicious HTML...
Posted by: babada at August 6, 2008 07:45 AMyeah, didnt you watch that episode of Mythbusters!?!?! ;o)
i drive a box (ie a 1996 VW jetta) so nothing really helps my gas mileage. i was really jealous to see how sweet ben's "hog" is. it re-invigorated my enthusiasm for 2 wheeled transportation. now if only i had a bit of disposable income.
Posted by: dr gonzo at August 6, 2008 07:49 AMhmmm, well I am usually driving under 45, though occasionally I will hit 50. Usually when I am over 45 I have my windows rolled up (because of my precious hair!)
Dr G - sell your car, then you'll have disposable income. of course I have no idea what you'd do during the winter for transportation.
babada - I apologize for my malicious html :-)
The other thing is that perhaps Scott (my hubby) was correct when he said my experiment wasn't scientific. Although it makes you wonder how they got the statistic then. You can't really test it in the same place you test the MPG because there isn't any aerodynamic effect (the car is stationary and on rollers).... so that still leads me to the same conclusion of 'they're making it up'...
Posted by: 10lees at August 6, 2008 08:28 AMooh - NOW the EPA does REAL tests for gas mileage - OUT in the real world! - but I don't think that encompased this little one.
I think it's a great conspiracy to get you to use more water and wax (someone was PAID off) - what is a 7% savings on 24 mpg? oops - I can't find my calculator - I think it's more like .7% and they just misplaced that nasty little decimal point. :)
Now you have to buy a NEW car - that's right - they have 2 settings on the new GM models - economy - air and the regular air.
Yeah - Bleaus mentioned opening the windows and I just rolled my eyes (well kindof) thinking T doesn't open the windows - I've said this to her since she could open windows herself and she never did it ...
AW MAN! Are you saying that my wax job was for nothing!?!
Just kidding.
Sorry that it didn't help. BUT you DID make the world a more beautiful place, one car at a time.
you saw the box-on-wheels. it's not really worth enough to buy that pretty Genuine Stella in orange that i've coveted for so many years... ;o) ironically, i had a dream about that Stella last night - she and i were driving somewhere, free as birds! so glorious.
Posted by: dr gonzo at August 7, 2008 07:11 AMThe impact of either windows or AC really depends on the vehicle. If you drive a wedge and the cars coeficient of drag is really small, window opening will impact it quite a lot. If you drive a box on wheels (such as my pickup), opening the windows marginally adds to the drag.
Also, AC's affect on gas mileage depends on the power of the motor. For someone with a small economy 4-cylinder, running the AC compressor takes a larger percentage of engine power to turn. On a larger truck (especially one built for towing), the engine is usually making more power than is necessary just to push it around so flipping on the AC has a marginal effect.
So in summary, the 45 mph stat really depends on the vehicle.
Posted by: jeff at August 7, 2008 07:50 AMmy car is mostly aerodynamic, which is good!
Dr G - do you just want that bike so you can randomly yell 'stella' alot?
and I do too open my windows mom, just not that much when i was a child...
Posted by: 10lees at August 7, 2008 03:24 PM