John,
Well of course you would prefer to burn the good stuff. At the price you pay
for it, it's cheap at 100 times the price!! :)
JOe
HD50EL@aol.com wrote:
>
> In a message dated 06/12/2000 10:41:13 PM Eastern Daylight Time,
> mikech@sprynet.com writes:
>
> << Waste of money. If your car is not designed or altered to need it, high
> octane has no benefit. High octane fuels are designed for engines with very
> high compression ratios or forced induction (racing engines, aircraft, etc.)
> . High octane is not necessary at the compression ratios stock Spitfires
> run. A quote from Sportbike Performance Handbook "The value of high octane
> fuels in unsupercharged engines lies in the higher compression ratio they
> will tolerate without detonation. Simply replacing a lower fuel with a
> higher does nothing for power. Essentially, the octane number measures the
> temperature stability of a fuel molecule. To obtain the value of a higher
> octane number, the compression ratio must be raised."
> If your car is not pinging or detonating on the lower octane fuels, a higher
> one is just a waste of money. In fact it can and will reduce power in a
> lower compression engine. In small cylinder bore engines, such as the
> Spitfire, higher compression can be run with lower octane numbers because
> the distance the flame has to travel is smaller. I've used nothing but the
> 87 octane fuel in my 9:1 Spitfire with no problems at all. Just use the
> lowest octane you can without hearing pinging (sounds like coins in a jar).
> >>
>
> You missed one benifit from using high octane fuel, it burns at a slower
> rate, giving you better MPG! I get between 15-20 more miles out of a tank of
> gas using high octane fuel, than using the low octane fuel. It's well worth
> the extra money to me!
>
> John C. Smith
> 75 Spitfire "Bad Mojo"
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