Date: Tue, 09 May 2006 09:52:43 +0100 From: Pooh Bear <rabbitsfriendsandrelationsnospamail.com> Subject: Re: Regular gas in a 9.5?
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