Originally Posted by cepheid
You said, "all else being equal." I, however, did not. What I specified was, "higher compression,
smaller displacement, same performance." The Lamborghini has, what, 2.5 times the displacement of the Civic? And the Lamborghini has, what, about 3 times the horsepower? (I'm ballparking here because I'm too lazy to look up the real numbers, but I'm reasonably confident that I'm fairly close to the true numbers.) So, the two are not comparable because the higher-compression engine has a larger displacement and much higher performance. A more correct comparison would be between two cars with similar horsepower.
(
EDIT:I looked up the numbers, and I was damn close with my ballpark estimates. The Civic engine is 1.6L and 115hp, the Lambo was 3.9L and 385hp. Unless I looked up the wrong Civic... but then I'd still be reasonably close.
)
Although both are internal combustion engines, both designs are different in respects to bore/stroke in regards to power generation. There is a fundamental difference between how each achieve their power. Each has their own school of thought. Therefore, it is almost impossible to compare two different manufacturers/engine fuel/power consumption without taking into their account of the design.
Generally you will find that...
Honda= lower displacement, small bore, long stroke, and high rpm's. This equates out to lower torque numbers, but higher hp numbers.
Lambo= Medium displacement with a square bore/stroke and moderate rpm's.
Regardless if you really want to know, Gas is gas in regards to the amounts of energy per unit of gas. However- the higher the octane, the more kenetic energy it is capable of producing rather than heat- the byproduct. Therefore generally the fuel can be compressed at a higher rate, and will not detonate, thus creating more power per cycle.
I hope you can understand this because i'm exhausted.