Dynamic compression ratio
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| − | + | The following are different static compression ratios (SCR) with a 3.48" stroke and different camshaft intake closing points @ 0.050" tappet lift on Keith Black's dynamic compression ratio calculator. The calculator, starting at 8.25:1 SCR. The dynamic compression ratio (DCR) has been kept at just over 8.0:1, a figure that is acceptable for use with today's pump gas with a little cushion: | |
*Static CR....Intake closing point @ 0.050"....Dynamic CR. | *Static CR....Intake closing point @ 0.050"....Dynamic CR. | ||
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*12.00.......68............8.017........................................................................................................ | *12.00.......68............8.017........................................................................................................ | ||
| − | Now, it's unclear where these Keith Black DCR calculator dynamic | + | Now, it's unclear where these Keith Black DCR calculator dynamic compression ratio readings are taken; at cranking rpm or at max efficiency rpm. According to the DynoSim software, maximum cylinder pressure is made at or near the torque peak. So, the fact that a motor is not detonating at low rpm does not mean that it will not detonate at, or close to, the torque peak. |
These numbers may not mean anything at all, but they do illustrate that you cannot just pick a cam out of thin air like a lot of fellows do and expect it to work best for your particular combination. | These numbers may not mean anything at all, but they do illustrate that you cannot just pick a cam out of thin air like a lot of fellows do and expect it to work best for your particular combination. | ||
[[Category:Engine]] | [[Category:Engine]] | ||
| + | [[Category:Cylinder head]] | ||
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