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Message text written by INTERNET:mrc01@flash.net
"Torque may give some guys hard-ons, but it doesn't by itself make
the car go fast. For that you need power.
"
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The more torque you can design into an engine at 2000-2300 rpm, the quicker
you will emerge out of an autocross turn. This factor is determined by a
combination of stroke length and cam design. As always, there are
tradeoffs. A long-stroke engine, common in the '30s (i.e. British sports
cars of the '50s) are also prone to break sooner rather than later.
A major factor in the historic Miller/Offenhauser engine's success
was its rather long stroke delivering "tons" of torque at low rpm. Its four
cylinders shook a lot, too. Eventually a V8 over-powered the Offy but even
today some of the fastest engines are reverting to ever longer strokes just
under four inches. The over-square engines with a bore larger than the
stroke deliver their power near the top of their rpm range. We are now
seeing more (race engine) manufacturers favoring bore and stroke of
near-equal dimensions.
If the power curve can remain more or less flat after the engine hits its
strong point, you will continue to accelerate. That's what will win in
autocrossing.
The above is a glittering generality as a high-horsepower car not
saddled with too much weight will always beat you, especially if the course
includes long straights over 250 feet. <G>
--John Kelly
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