Reply With QuoteOn average my 2003 RAM 3500 CTD gets about 1.5 MPG less with the AC on while not towing. Oddly enough, while towing it does not seem to make a difference.
Fuel consumption with AC on?
I'm pretty curious about the fuel penalty for AC use; anyone with a scan guage II or a car with a 'puter can chime in here; I am interested in Miata's and other cars as well...
Say your cruising along at 65mph with ac off, then turn it on; how much does the mpg's drop? Most of those fancy car computers give you instant feedback...
Also, what is the fuel consumption, running on a flat road, at 60? Then 65? Then 70?
I guess I have been a bit obsessed with fuel economy at times.
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On average my 2003 RAM 3500 CTD gets about 1.5 MPG less with the AC on while not towing. Oddly enough, while towing it does not seem to make a difference.
What about the old argument concerning drag.
Windows/top down, no AC causes more resistance on the moving car, correct? Windows/top up, less resistance. I can't imagine it making a big difference either way in a Miata.
No scangauge here, but if I run a full tank without using the A/C at all, I get between 29 and 30 mpg. If I run the A/C half the time, (for example, A/C driving to work, no A/C driving home,) I get about 28 mpg for the tank, so I'm guessing the penalty is about 2.5 mpg or so for my '99 miata.
Mike Walsted - Not an expert, just a data point.
1999 Miata
2003 MIata
1999 Miata
2001 Kia Rio
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