# using ac and getting terrible gas mileage.
**URL:** https://forums.speedlife.net/t/using-ac-and-getting-terrible-gas-mileage/49962
**Category:** NYSpeed Automotive
**Created:** [June 13, 2008, 2:18pm UTC](https://forums.speedlife.net/t/using-ac-and-getting-terrible-gas-mileage/49962 "2008-06-13T14:18:10Z")
**Posts on this page:** 2
**Page:** 2
### Author:  [@Silver](https://forums.speedlife.net/u/Silver)
#### Post date: [June 14, 2008, 3:11am UTC](https://forums.speedlife.net/t/using-ac-and-getting-terrible-gas-mileage/49962/21 "2008-06-14T03:11:22Z")
Or you could sawzall the roof off and make it an open top.
I know, I’m being really helpful.
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### Author:  [@Karter](https://forums.speedlife.net/u/Karter)
#### Post date: [June 14, 2008, 3:27am UTC](https://forums.speedlife.net/t/using-ac-and-getting-terrible-gas-mileage/49962/22 "2008-06-14T03:27:05Z")
> [@HotRodKid](#):
>
> then your using your a/c when it makes the biggest impact on milage, and have your windows open when it makes the biggest impact in milage
>
> say a/c uses 20hp (constant no matter how fact your moving)
>
> and say that the aerodynamic drag from having the windows down is equal to:
>
> 10hp loss @ 30
> 20hp loss @ 45
> 30hp loss @ 60
>
> obviously it would be more efficient to have the windows open below 45, and the a/c on above 45
True, I just based it on how unbareable It was to drive thru buffalo, stop and go @ 30mph, when its deadly hot and I have no ac.
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