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| − | Just for grins, I calculated different static compression ratios 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 went ka-flooey on 8.00, so we'll start at 8.25 SCR. I kept the DCR at just over 8.0, a figure that is well accepted for operation of the motor on pump gas with a little cushion...
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| − | Static CR....Intake closing point @ 0.050"....Dynamic CR
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| − | 8.25........10* ABDC......8.010.........................................................................................................
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| − | 8.50........20............8.012.........................................................................................................
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| − | 8.75........27............8.022.........................................................................................................
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| − | 9.00........33............8.018.........................................................................................................
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| − | 9.25........37............8.061.........................................................................................................
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| − | 9.50........42............8.029.........................................................................................................
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| − | 9.75........46............8.016.........................................................................................................
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| − | 10.00.......49............8.038.........................................................................................................
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| − | 10.25.......52............8.043.........................................................................................................
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| − | 10.50.......55............8.029.........................................................................................................
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| − | 10.75.......57............8.069.........................................................................................................
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| − | 11.00.......60............8.022.........................................................................................................
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| − | 11.25.......62............8.038.........................................................................................................
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| − | 11.50.......64............8.042.........................................................................................................
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| − | 11.75.......66............8.035.........................................................................................................
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| − | 12.00.......68............8.017.........................................................................................................
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| − | Now, it's unclear where these dynamic cr readings are taken, at cranking rpm's or at max efficiency rpm's. But I can tell you this from playing with the DynoSim, max cylinder pressures are made at or near the torque peak. So, the fact that a motor is not detonating at low rpm's does not mean that it will not detonate at or close to the torque peak.
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| − | 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.
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