Any normally aspirated, (non turbo-super charged) engine will lose
approximately 3% power for each 1,000 feet of altitude. This is due to
the reduced cylinder charge. If the O2 sensor is working, it will
compensate for the slightly lower O2 level in the atmosphere. At 9k
feet, you have lost almost 1/3 of your engine. This effect is why lower
octane fuel is sold at higher altitudes.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf
Of Phaedra Savage
Sent: Wednesday, December 17, 2003 3:23 PM
To: vanagon@GERRY.VANAGON.COM
Subject: '85 Westy - Major power loss at altitude

Hi List,
Since start of Mex trip Dec 5th, my Mexicali Rose has been purring along
beautifully, as she has done since '99 when we made our first round-trip
to mainland Mex from N CA.  And by the way,  Rosie's odometer flipped
over to 250,000k original miles just a day over the border!!!  She looks
great and runs like new on her second engine.  Well, almost...

Here's the rub:  soon as we reach altitude of 2k feet, she loses power
on grades; by 4k feet, she's realling feeling it; and at 9k feet she's
crawling on her belly like a reptile at 20 mph!!!  

What's up? I'm hoping all that's required is a turn of a screw
somewhere.  I've got the Bentley along, naturally.  Please advise by
p-mail ASAP, as we're currently at 5k feet, but have plans to get into
some REAl monta�as pronto.  Except at altitude, she runs great...
Thanks, or, as we say in Mexico: �milgracias!
Phaedra & Mexicali Rose
'85 Wolfsburg Westy

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