Are you driving an air-cooled model? A Westy?  From your MPG figures I would guess so.

Any engine gets more power at sea level than at altitude due to the increased atmospheric pressure. Because the air-cooled engine has a much lower compression ratio than the waterboxers,  it is lower powered and gets worse MPG than they do. The classic cure for altitude is a supercharger, which was invented for aircraft engines to deal with this problem. I don't know of any superchargers for air-cooled vanagons, and even if you had one, you couldn't use it at sea level without cooking the engine. Probably the only practical cure for a Vanagon is to install an inline 4 watercooled engine from a Jetta or the like, which several folks on the list have done.  It would probably be too much hassle on an aircooled, though, since there's no radiator or plumbing already installed. People do convert older diesel Vanagons to gas engines, which have a lot more power for the same engine size.

At 01:04 PM 6/30/01 -0700, you wrote:
>I submit that driving a Vanagon is more challenging here in the West.  I
>notice my van runs better and better as I approach sea level -- more power
>and better MPG.  I live at about 4500' and get 12 to 13 MPG.  At sea level I
>get 3 MPG more.  Is there a fix for this other than moving East
>(unthinkable)?
>
>The highest point in Pennsylvania is lower than the lowest point in
>Colorado.  This is true for several Eastern states.  The highest point in
>Florida is the top of the bridge connecting Tampa-St. Pete.
>
>Bill -- Southeast Arizona -- www.freeholder.com