AC question!!! Which saves more gas?!?!

wstar · 08-25-2011, 07:35 AM

If cycling your AC on and off manually saves gas, it's just because you're making the average temperature higher than it would be if you left it on all the time at the coldest setting. In any case, even on older cars the A/C compressor cycles on and off while you have it "on". It's just part of how the whole system operates.

The A/C in the Z is thermostat controlled anyways. IMHO, set all the dials to "Auto" and set the temperature at your comfort vs cost limit. The colder you set the dial, the more gas you'll suck over time. It will be far less trouble and just about as effective.

A related issue that's been debunked before: rolling down the window vs running the A/C. Assuming you can bear the heat level of running with the windows down and no A/C to save gas, it actually does save gas at low speeds (city streets). However, on the highway, the parasitic drag on the car from having the windows open wastes more gas the running the A/C, so don't do that.

08-25-2011, 07:35 AM	#7 (permalink)
wstar A True Z Fanatic Join Date: Mar 2009 Location: Houston, TX Posts: 4,024 Drives: too slow Rep Power: 3595	If cycling your AC on and off manually saves gas, it's just because you're making the average temperature higher than it would be if you left it on all the time at the coldest setting. In any case, even on older cars the A/C compressor cycles on and off while you have it "on". It's just part of how the whole system operates. The A/C in the Z is thermostat controlled anyways. IMHO, set all the dials to "Auto" and set the temperature at your comfort vs cost limit. The colder you set the dial, the more gas you'll suck over time. It will be far less trouble and just about as effective. A related issue that's been debunked before: rolling down the window vs running the A/C. Assuming you can bear the heat level of running with the windows down and no A/C to save gas, it actually does save gas at low speeds (city streets). However, on the highway, the parasitic drag on the car from having the windows open wastes more gas the running the A/C, so don't do that. __________________ 7AT Track Car! Journal thread / Car setup details

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