Date: Tue, 25 Jan 2000 08:27:08 -0500 From: Four Weis <mweinopsamcom> Subject: Re: Regular or Premium in 2.3T?
Bill Hays wrote: > I've had the same experience as Julie, also in a '91 9000 2.3l turbo -- > lesser grades (below 92 octane) won't ping or knock, thanks to the > anti-knock circuitry, but my gas mileage with, say, 89 octane (I've never > tried 87 octane) is about 2-3 mpg less in my daily driving (a mix of > neighborhood, densely urban and freeway driving in the Seattle area) and > noticeably reduced performance. The 2-3 mpg decrease in mileage offsets > any price gain (about $0.10 to $0.15 per gallon) from the lower octane > fuel. The lesson: stay with the premium gas -- better mileage, better > performance, lower cost per gallon. I have a Saab and a Volvo turbo and my experience has been the same as Bill. I get more miles per gallon with premium, enough to make it less expensive per mile. Don't fall into the trap of only looking at the price per gallon, look into the cost per mile. The anti-knock computer controlled system works by retarding the timing. Does anyone have any knowledge about the effect on power output from retarding the timing? Judging from the decrease in mileage, there is some relationship.
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