"JIM HOLSONBACK" bravely wrote to "ALL" (26 Apr 05  16:04:00)
 --- on the heady topic of "Gas Prices vs. Mileage"

 JH> Hello, ALL.

 JH> Our 'family' car here is this older Buick sedan - a '98 LeSabre.
 JH> Engine is the GM 3.8L V6. (I've had several cars with this block over
 JH> the years, with generally good service).  IMO it gets decent gas
 JH> mileage on the recommended 87 octane. I bought gas here last week at
 JH> Costco, and it was 2.03 for 87 and 2.13 for the 91 octane. (A bit less
 JH> than 5% price premium). This is unlike a lot of the commercial gas
 JH> sellers, where the high-test is typically $0.20 or so more than the
 JH> regular.
 JH> I don't take many long trips, mostly local but not much stop and go
 JH> in heavy traffic. I was thinking if I'm averaging 20mpg now, and could
 JH> get 21.0 or better with the higher octane with my type driving of it,
 JH> I'd be doing OK.

 JH> I'm surprised I haven't seen any articles about this situation. My
 JH> question- might I be able to get more than 5% mileage increase if I
 JH> start running the high-test?

No, octane number relates to how fast the gasoline explodes. A higher
octane number causes the ignition to slow down and lengthen the burn.
It won't give better milage in an ordinary engine but it might improve
it slightly in a medium compression motor or a very large cylinder.
Perhaps if you had a 4 cylinder motor with the same 3.8L volume it
might make a difference but I don't know how much off hand. Few
modern engines require the higher octane to keep from knocking.
There has always been some hype in the octane numbers business.
Refiners make regular to run well in the great majority of engines.
But sometimes they play games such as with the MDHT (?) fiasco...

 M*i*k*e

... When in doubt, blame the hardware.
--- Blue Wave/DOS v2.30