Quote:
Originally Posted by Modshack
Euro/Asian cars tend to make their horsepower at higher revs at the sacrifice of torque. The smaller the displacement and the greater the number of cylinders generally result in less torque. American cars have always been Big cubic inch motors in relation to their horsepower. Big displacement equals big torque. The Torque and horsepower curves always cross at 5300 or so RPM's on a dyno(I forget the exact number off hand). Torque is what you feel when you drive and tip into the throttle. More is nice.
Dry sump oil systems may have some reduced losses due to the fact that there isn't oil being thrown about the crankcase to slow things down. Porsches, Z06's are both dry sump systems.
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Actually, I don't think you're entirely correct...
It comes down to bore vs stroke. An engine that has a longer stroke than another, even given equal displacement, will have more low end torque. The flip side is that it won't have as much top-side RPM as there is much more reciprocating mass (and distance) therefore the maximum speed the engine can spin goes down...
A good example is to look at motorcycle engines...
Your typical V-Twin has a long stroke to small bore ratio. Result - lots of low end torque, decent HP numbers, and not very high RPM limit - on the other side you have a sport bike engine, these typically have smaller stroke and larger bores. Result - high reving engine with insane levels of HP for the displacement, and not really a whole lot of torque.
The ratio of bore vs stroke, can be referred to square, undersquare or oversquare, though I really don't remember which designation is which condition.