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Date: 9 May 2006 07:48:59 -0700 From: "Michael Hudson" <mahnospamotcommunications.com> Subject: Re: Regular gas in a 9.5?
Pooh Bear wrote: > Michael Hudson wrote: > > > the book says to use at least 90 octane gas, > > > > I just put my first tank of 89 octane gas - hoping for the best - > > Why still not even 90 octane ? The advice is *at least* 90 octane ! > > " Occasionally you get some genius who takes the opposite tack--he spends an > extra 10 or 20 grand buying a high-performance car, then decides he's going to > save three bucks per tankful using regular instead of premium as specified. He > figures as long as the engine doesn't knock he's OK. Wrong, carbon monoxide > brain. Car engines nowadays contain knock sensors that detect detonation and > automatically retard the spark to compensate. The delay means maximum gas > expansion occurs when the piston is farther along in its downstroke and thus > there's more room in the cylinder head. This reduces peak cylinder pressure, > eliminating knock but also giving you less power and poorer mileage. " > > http://www.straightdope.com/columns/041008.html > > Graham I appreciate the 'straightdope,' Graham. I'm not trying to be cheap; I'm just trying to avoid the shedding of any shekels that I might otherwise have and hold, for better or for worse. What Fred said below, re: the 87 v. 89 v. 90 situation, seems to make sense to me. On the other hand, what I don't know about cars and engines is staggering, even to me. The Straightdope article was a help, and I need all of that that I can wrangle. Cheers, M
