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Old 01-29-2008, 07:49 AM
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gpsman1 gpsman1 is offline
Hybrid Technologist
 
Real Name: John
Location: N.Colorado & S.Minnesota
Hybrids: 2005 Diet Ford Escape FWD, 2000 Honda Insight
Posts: 2,547
Default Re: 87 vs 91 octane for better mpg?

Quote:
Originally Posted by livvie View Post
The engineering group will sign off saying it can be tuned to the lower octane level but actually can perform better at the higher octane level. I believe the Prius engine (atkinson cycle engine) is such a case.
The Atkinson type engine behaves the opposite of a high compresson race engine. The lowest octane available is the best choice. I use 85 octane in the Rocky Mountain states, and it works great when I drive a tank down to near sea level.

Octane is "anti-knock"... and the lower compression due to the atkinson cycle makes knocking almost impossible with even the lowest octane.

( I heard Poland sells 80 Octane, and Russia... 78 Octane... I'd like to try it some time... but it's pretty far for me to get some! ) -John

Numbers below from 85 Octane... 4,000 pound SUV too!

.

Gasabout $0.05/mi
Gasabout $0.09/mi
E85about $0.09/mi

WORLD RECORD MTE?
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