Quote:
Originally Posted by Henry Schmidt
If the actual compression ratio of a piston is 10.2 on a 66mm crank, the compression ratio on a 70.4 crank would be 10.8.
Still a very nice CR for a twin plug engine. As a general rule, .5 change in the compression between 66 and 70.4 is expected.
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Jeez Yoda, I did say approximately 11:1.
Given the same combustion chamber volume, the CR would increase by the ratio of the cylinder volumes.
Assuming the 89 X 66 2.5 liter has a CR = 10.2:1
The 89 X 66 2.5 liter has a 410.38 cc volume and the 89 X 70.4 2.6 liter has a 436.76 cc cylinder volume.
CR of the 89 X 70.4 = 436.76/410.38 X 10.2 = 10.8556752278
