Eric,
Octane rating is not a measure of the energy in the fuel, it's a measure
of how much energy it takes to make the fuel burn. (Called activation
energy in chemistry circles).
For instance: you rebuild your '68 MGB with a shaved head and flat top
Hepolite pistons. Now you've got mucho compression, and that compression
is energy, so much energy in fact, that while the piston is going up,
your air-fuel mixture with 87 octane gas explodes before its time.
This is knocking, pinging, pre-ignition, detonation, depending on how
technically astute you care to sound and how severe it is.
So you now run racing fuel in you Mean MG. This stuff takes more energy to
fire, so you can actually use the high compression instead of blowing
holes in the tops of those theoretical Hepolites.
Want some exercise? Move someplace *cold* (like a trip to Antartica), take
some low compression econo-box, fill it with that same racing fuel, and
it will not start.
As far as power is concerned: an engine makes the most horsepower when
it is on the verge of pre-ignition. Easy for a computer to do, much harder
to set up for with carbs and points type distributors.
As far as lead is concerned: I never run leaded fuel, and I've never
seen any valve problems in my MGs.
As far as the metric stuff is concerned: Geeze. Canadians. Australians.
Even the Home Country. Are we Americans the only ones left who will
stand up against the French?
Happy Miles-per-Gallon,
-Keith Wheeler
Team Sanctuary http://www.teamsanctuary.com/
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