Having made many NY to Florida trips over the years and generally
traveling around 70 if conditions permit, the AC easily robs 1 mpg and
higher speeds make it worse the compressor is turning much faster, working
harder than needed. I've done as bad as 15 mpg on those trips with AC on.
Without, I usually get 16 to 17. This is for the Syncro Westy.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Mike S
Sent: Tuesday, August 28, 2007 9:03 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: MPG and AC - Mythbusters

At 08:27 PM 8/28/2007, Maggie Dew wrote...
>Sorry, I thought the p-mail about mythbusters was cc'd to the list (I
>only
>get digest).
>
>Apparently episode 38, Season 3, concluded that above 50 mph you get
>better
>mpg with AC on and windows up (drag factor), but below 50 it is best
>to have
>AC off and windows down.

Too many variables. Mythbusters is entertainment, not science. R-12 or
R-134a? Modern variable displacement compressor? What difference does
the inside/outside temperature differential make? Were the aerodynamics
of the vehicle measured to determine the difference (windows
open/closed)? How does that difference compare with other vehicles
(specifically the Vanagon, where I can't imagine you can do much to
make it worse, including opening the windows)?