Quote:
Originally Posted by buzz_42
Hey everyone!
I just got back from an 800+km trip.
I have the PLX Kiwi monitoring my mpg.
On the last leg of my journey, I decided to play around with my A/C.
I noticed that on a consistent flat road, when I turned on my a/c, my instantaneous mpg went down between 4 and 6 mpg. (depending on the road)
I am totally a newb. At tech school we were taught that a/c didn't take away power or mpg. This blew my mind!
Has anyone had a similar experience?
Also, I challenge you to find the flattest road you can and set your cruise and test it. A/C on and off. See what your mpg does.
Thanks for being patient if this is a total newb question! 
- Buzz |
I tried your challenge last Summer on a very slightly downhill section of road with my Mustang. Cruise control was set at 35 MPH. Scangauge indicated 80 MPG with A/C off. It dropped to 60 MPG when I turned on the A/C. 20 MPG/25% difference!
Under those low load circumstances.
I'll have to check the difference in GPH when I get a chance.
Living in the mountainous part of Arizona, I rarely use A/C except on road trips. When I need to use A/C, I set it on recirculating and "pulse & glide" the compressor.