You are confusing compression ratio and compression!

See wiki article http://en.wikipedia.org/wiki/Compression_ratio

My point is important, the compression (psi) determines the uncontrolled combustion not the compression RATIO. This is the reason A/M engines get better fuel economy. They extract more energy from the burning of the fuel and less goes out the tail pipe and into the cooling system. Its a thermodynamics thing. I a nit picking this because this was going to be my thesis for my ME degree in 1979.

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Mark Smith
Master Certifited Technician
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