A naturally aspirated engine will lose 3% for 1,000 feet of altitude.
This goes for gasoline or Diesel. The major factor is decrease
atmospheric pressure which will result in decreased cylinder charge.
This why lower octane fuels such as 83 or 85 are used in high altitude
areas.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@GERRY.VANAGON.COM] On Behalf
Of Pensioner
Sent: Friday, June 06, 2003 8:13 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Degrading Comments

Engine performance degradation as function of altitude?  Data, numbers,
curves, experiences?  NB it has been pointed out that the air resistance
actually decreases at altitude.  I'm looking for engine performance
numbers
independent of van configuration.

p