|
|
Line 1: |
Line 1: |
− | {{youcanedit}}
| |
| | | |
− |
| |
− |
| |
− | 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.
| |
− | *8.25........10* ABDC......8.010........................................................................................................
| |
− | *8.50........20............8.012........................................................................................................
| |
− | *8.75........27............8.022........................................................................................................
| |
− | *9.00........33............8.018........................................................................................................
| |
− | *9.25........37............8.061........................................................................................................
| |
− | *9.50........42............8.029........................................................................................................
| |
− | *9.75........46............8.016........................................................................................................
| |
− | *10.00.......49............8.038........................................................................................................
| |
− | *10.25.......52............8.043........................................................................................................
| |
− | *10.50.......55............8.029........................................................................................................
| |
− | *10.75.......57............8.069........................................................................................................
| |
− | *11.00.......60............8.022........................................................................................................
| |
− | *11.25.......62............8.038........................................................................................................
| |
− | *11.50.......64............8.042........................................................................................................
| |
− | *11.75.......66............8.035........................................................................................................
| |
− | *12.00.......68............8.017........................................................................................................
| |
− |
| |
− | 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.
| |
− |
| |
− | [[Category:Engine]]
| |
− | [[Category:Cylinder head]]
| |