Dynamic compression ratio
(New page: 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 ...) |
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| Line 2: | Line 2: | ||
Static CR....Intake closing point @ 0.050"....Dynamic CR | Static CR....Intake closing point @ 0.050"....Dynamic CR | ||
| − | 8.25........10* ABDC....8.010 | + | 8.25........10* ABDC......8.010......................................................................................................... |
| − | 8.50........20 | + | 8.50........20............8.012......................................................................................................... |
| − | 8.75........27 | + | 8.75........27............8.022......................................................................................................... |
| − | 9.00........33 | + | 9.00........33............8.018......................................................................................................... |
| − | 9.25........37 | + | 9.25........37............8.061......................................................................................................... |
| − | 9.50........42 | + | 9.50........42............8.029......................................................................................................... |
| − | 9.75........46 | + | 9.75........46............8.016......................................................................................................... |
| − | 10.00......49 | + | 10.00.......49............8.038......................................................................................................... |
| − | 10.25......52 | + | 10.25.......52............8.043......................................................................................................... |
| − | 10.50......55 | + | 10.50.......55............8.029......................................................................................................... |
| − | 10.75......57 | + | 10.75.......57............8.069......................................................................................................... |
| − | 11.00......60 | + | 11.00.......60............8.022......................................................................................................... |
| − | 11.25......62 | + | 11.25.......62............8.038......................................................................................................... |
| − | 11.50......64 | + | 11.50.......64............8.042......................................................................................................... |
| − | 11.75......66 | + | 11.75.......66............8.035......................................................................................................... |
| − | 12.00......68 | + | 12.00.......68............8.017......................................................................................................... |
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. | 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. | ||
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. | ||
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