I just saw on Mythbusters.

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Dec 5, 2004 | 09:00 AM

tozoM8

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I just saw on Mythbusters.

At 45 Mph your vehicle uses 15% more gas with A/C on windows up versus A/C off windows down. The put 5 gallon gas in two identical Ford SUV and the one with A/C off ran 30 miles more on the track. However the car's trip computer with A/C on showed slightly better gas mileage. So looks like they fool us to buy more gas.

Dec 5, 2004 | 09:38 AM

badmyan

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The results I think are flawed

One of my posts last week was about this same item on mythbusters.

The problem I had is that drag does not increase linear with speed. The MPG was checked with the ECU at 75MPH while the test was performed at 45MPH.

I think it's a perfectly plausable argument that there is a cross over point between A/C vrs Windows open. A/C load would tend to be constant and could even drop as speed increases (more airflow accross it's cooler).

Also did they both truly have the same amount of Gas.... There method was questionable, Were they driven absoulotly identically, no speed fluctuations etc etc etc.

Dec 5, 2004 | 11:13 AM

taga8

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Re: The results I think are flawed

Definitely flawed, why did they not have a base line car with the windows up with no A/C also? When I saw this I thought that this is a very poor comparison, who drives for an hour without changing speed or stopping, and if you do why would you worry about gas mileage, just be glad that there is no traffic!!!