I finally remembered to bring in Vizards book 'How to Build
Horsepower.' In it, he has a chart which lists the, "power and torque
increase given by a higher compression ratio for a street engine with
a relatively short duration cam" I'll type in a couple numbers...
8:1 9:1 10:1 <--- original compression ratio
_________________________
8:1 | 0
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9:1 | 2.0 0
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10:1 | 3.7 1.7 0
|
11:1 | 5.2 3.2 1.5
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12:1 | 6.5 4.5 2.8
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^
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new compression ratio
Also note, this is based on the traditional mechanical
compression ratios we are familiar with.
A few points to consider. First, this is an increase in
thermodynamic efficiency for your engine. So you can expect an
increase in engine economy. Second, I would try to increase the
compression ratio by boring out the cyliders. This will increase
both the swept and total volume of the engine. An engine bored
out to give a 10:1 compression ratio will produce more power than
an engine with the head milled to give 10:1
woodruff@caen.engin.umich.edu
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