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).
MikeC
>burning Methanol. He said it was aviation fuel ! 140 Octane, he buys it at
>the local private airport, this caused me to think,,, what would a couple
>gallons of that do in our 8 gallon tanks to the heads and valves or our
>spits ?
>
>I would think it would burn very well if it didn't burn the tips off the
>plugs or worse burn the valves clean out of the head.
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