Date:         Fri, 14 Mar 1997 14:16:58 -0500 (EST)
Sender:       Vanagon Mailing List <vanagon@vanagon.com>
From:         SyncroHead@aol.com
Subject:      Re: Gasoline Grade?

In a message dated 97-03-13 22:19:16 EST, scr@pacifier.com writes:

>  I always burned Chevron Premium in my '91 Westy. But, one time I had to
put
>  87 octane fuel in it, not being particularly concerned about it.
>  Driving home to Portland, OR from Vancouver, WA everyday, I got used to
the
>  gears needed at various points on the trip.
>  One day I was climbing the gentle, multi-mile grade out of the Columbia
>  River valley when I suddenly realized I was in the usual left lane but I
>  was losing speed. I had this sudden sickening feeling. Oh, Gawd! What's
>  wrong?!
>  Within a few seconds I remembered I had put Regular fuel in it. Ruby just
>  didn't have the explosive power it usually did so I had to move to the the
>  middle lane.
>  It ran just as smooth as it did with 91 fuel, just without as much torque.

Higher octane gases don't inheriently produce more power or torqure, nor will
they create any better gas mileage.  They just have the ability to resist
compression detonation beter than lower octane gases.  That said, it may have
been some other characteristic of that particular batch of gas you used, that
could have lowered it's available power - but not just the octane number.

Now, in an engine that can adjust timing with the aid of a knock sensor (not
any Vanagon engine, but found in Golfs, etc.) the adjusted timing can create
more power while using a higher octane fuel.  Another item often leads people
to believe higher octane fuels have more power.  Race cars use higher octane
fuels, don't they?  Yes, but they create the additional power in part because
they have high compression ratios, not because they use high octane gas.
 Having the high compression ratio causes them to require high octane fuel,
so that it won't detonate under the higher pressures in these engines.

Regards,
Jim Davis
87 GL Syncro
88 GL Wolfsburg