A/C and Gas Mileage Question

[CAJUN C4]

Coming in to work today in the 95', I noticed when I turned off the A/C my Instant Mileage went up 3-4 MPG's..You find this as well? I thought the rule of thumb to be about 2 MPG.?

 

[TedC]

Cajun, I found that using the instant MPG provided misleading results. By resetting the average MPG before each test while driving 5 miles on a flat highway provided for a better comparison (A/C cycling). Delta was 2 MPG @ 60 MPH @ 75 degrees on a 1989 L98.

 

[Sunstroked]

The boys on discovery channels myth busters did a test on a/c vs 2X60 air. I'm sorry I don't remember the exact results, but believe it was pretty close, the added drag from rolling windows down vs the engine drag, smoother aerodynamics and a comfortable cockpit weren't that great. As for me, it was 110 deg today here in AZ. My R12 charged a/c was pumping cold air, and will continue to pump cold air until Sept. Damn the gas pump.

 

[compyelc4]

cajunc4-

I also have a '95 stock with 2:07 rear. My mpg (per computer) robs about 3 mpg from mine also. This is steady state 65-70 mph interstate. AC system checks out fine and engine runs smooth and strong, and I can actually feel a slight tug each time the compressor kicks in. Wouldn't think with 300 hp and 3:07 rear you would feel the little tug would you? 3mph loss versus nice cool air on a freakin' hot day does not bother me a bit.

 

[compyelc4]

Nuts! I meant 3:07! Long day.................... Hate it when I play the fool.

 

[Schrade]

cajunc4-

I also have a '95 stock with 2:07 rear. My mpg (per computer) robs about 3 mpg from mine also. This is steady state 65-70 mph interstate. AC system checks out fine and engine runs smooth and strong, and I can actually feel a slight tug each time the compressor kicks in. Wouldn't think with 300 hp and 3:07 rear you would feel the little tug would you? 3mph loss versus nice cool air on a freakin' hot day does not bother me a bit.

2.07 ??? :eek

That has GOT TO be good for a 190+ top end... probably still tachin' 5k too yup uh huh.