ColesAircraft

iTrader: (1)

This may be a dumb question - but back in the day I used to drive a Triumph TR7, and when you turned the a/c on, the car would stall if the RPMs were too low.

I have a G37S coupe. I obviously don't have to worry about the a/c killing the engine like that, but how much horsepower does it draw when it's on?


Thanks!

Black Betty

iTrader: (60)

The only way to possibly know that would be to do back to back dynos with the A/C on and then off. Nobody has done that so its not known. Minimal.

Coprolite

Related in a tangential manner, turning off the A/C during winter driving bumps my MPG by more than 10%(barely 19 to 21+).

mtrsprt

Never run the compressor if you don't need to. If your A/C light is on, your compressor is running to control the climate/humidity in the cabin. Crack a window, or use the vent if you do not need to defog/ice anything....

Another note: When you go WOT, your compressor will dis-engage. So as long as your foot is to the floor, the compressor will **** off momentarily.

movinon

The A/C on my cars, in SW Florida, are always on. I know a lot of cars are setup to temporarily disengage the A/C when you fully depress the gas pedal, don't know if that's the case with the G37.

Black Betty

iTrader: (60)

It is. Try it on a hot day and you'lll see.

Advice to run with the A/C off is kind of silly for those of us who live in hot and humid climates. I never turn off the compressor. Why would I? The only time that my A/C compressor has been off is when it was on a dyno (once) and when it's been on a track a few times.

I tried measuring the fuel consumption both ways in a controlled test. I drove 220 highway miles to San Antonio with the cruise control set at 71. I drove the exact same route back with the cruise set at the same speed with the A/C off. Difference of .4 MPG. Not worth sweating like a ***** in church for the 9 months out of the year when it's hot and humid here.

Coprolite

Agreed. I have see different MPG on trips based upon the winds. Driving to WTX and on the way back might be 5 mpg different just due to prevailing winds. I only turn off my compressor during the winter. Fort Worth is nowhere near as humid a Houston, so the driving force is temperature. The A/C will probably be on almost all the time from March onward.