Thread: Average Mpg
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Old 02-27-2007, 10:46 PM
phil47 phil47 is offline
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Quote:
Originally Posted by sageriders
When at high altitude in Colorado, or in the midwest, where ALL the gas has ethanol added, I used 91. But back here on the "flats", it's 89 all the way.
Actually, it's the REVERSE for high altitude. The higher the altitude, the less the octane requirement (same goes for lower temps).

Good info on this here:

http://www.chevron.com/products/prod...i_octane.shtml

Unfortunately, engines also build less HP due to the lower barometric pressure... At 3700 feet elevation here in Calgary, the 4.4l V8 in my X5 which should make 315 HP will make closer to 280 HP

BHP loss calculator here:

http://www.wallaceracing.com/braking-hp.php
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