A/C Affecting Mpg? - Chevy Cobalt Forum / Cobalt Reviews / Cobalt SS / Cobalt Parts
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post #1 of 26 (permalink) Old 08-09-2010, 08:46 AM Thread Starter
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A/C Affecting Mpg?

so i read (or heard..cant remember) somewhere that having your a/c on makes your mpg worse? i dont remember where i read/heard it, but im just wondering if its actually true or not
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post #2 of 26 (permalink) Old 08-09-2010, 08:48 AM
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Yes, it's true. Anything that diverts power from the engine makes mpg worse by varying degrees. Having you headlights or stereo on will do it also, but to such a small degree that you cannot tell a difference.

Running my A/C usually takes 5-10% off my mpg.

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post #3 of 26 (permalink) Old 08-09-2010, 11:50 AM
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I definately also notice the power drain from the A/C. But, I haven't owned a 4 cylinder in a long time.
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post #4 of 26 (permalink) Old 08-10-2010, 07:52 AM
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Yes it steals power no matter engine size, so you will have less power and in turn reduced MPG. So does your alternator, that's why when you race you should have everything electrical turned off along with the A/C. A little fun fact, if you're aiming for the best mpg roll your windows down if you're going under 35 or so and use A/C above that. Also the when you use the defroster or recirculate the A/C is turned on automatically.

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post #5 of 26 (permalink) Old 08-10-2010, 04:21 PM
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AC sucks a ton of power. That compressor takes a good amount of power to turn when its clutch is enabled.

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post #6 of 26 (permalink) Old 08-26-2010, 06:00 PM
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Yeh turning off the a/c really opens up my 2.2 LAP, like a tune wouldn't be necessary. Only downside.....doing so in the Florida summer heat.

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post #7 of 26 (permalink) Old 08-27-2010, 11:40 AM
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No kidding. I finally got to drive my 2010 Cobalt with no A/C the last two mornings. Since I bought it July 3rd and it has been 100+ ever since, the A/C has been on its whole life. Without the A/C there is a very noticeable difference in performance. The difference is not this noticeable on my V-8s. I'm looking forward to driving this car in the winter.
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post #8 of 26 (permalink) Old 08-27-2010, 01:32 PM
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wait wait wait!!!! when i turn on the Re-circulation button my A/C turns on!?! W.T.F!?! is there a wire I can cut that makes the a/c not kick in?

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post #9 of 26 (permalink) Old 08-31-2010, 04:13 AM
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I almost never use the AC when I'm by myself and grudgingly when the wife's in the car with me. Not sure why...I just don't like AC.

I think most things I've heard or read agree with the speed < 35 MPH. windows open AC off and speed > 35 MPH. AC on windows closed.

BTW...my DIC mpg average is regularly breaking 40mpg...

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post #10 of 26 (permalink) Old 08-31-2010, 06:59 AM
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I keep my windows down. I'm just used to it, and like it. I'll use the A/C if it's raining and hot, but if I can have my windows down, generally they are.

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