Editing Dynamic compression ratio
Line 1: | Line 1: | ||
+ | {{youcanedit}} | ||
==Online calculators== | ==Online calculators== | ||
− | |||
*[http://www.wheelspin.net/calc/calc2.html SCR calculator] | *[http://www.wheelspin.net/calc/calc2.html SCR calculator] | ||
− | |||
− | |||
− | |||
− | |||
*[http://www.wallaceracing.com/dynamic-cr.php Wallace Racing DCR calculator] | *[http://www.wallaceracing.com/dynamic-cr.php Wallace Racing DCR calculator] | ||
− | *[http://www. | + | *[http://www.empirenet.com/pkelley2/DynamicCR.html Kelly DCR calculator] |
− | + | *[http://www.kb-silvolite.com/calc.php?action=comp2 KB/Silvolite DCR calculator] | |
− | + | If the intake closing (IC) point isn't known, it can be calculated by dividing the intake duration by 2, add that to the lobe separation angle (LSA). Then subtract any ground-in advance. Finally, subtract 180. This result does not need to have any amount added, like the KB calculator calls for. | |
− | + | ||
− | + | ||
− | + | ||
− | + | ||
− | This result does not need to have any amount added | + | |
− | + | DCR and pump gasoline== | |
It's worth mentioning that 8.5:1 DCR is considered to be the maximum for iron heads and 92 octane fuel (MON + RON divided by 2). | It's worth mentioning that 8.5:1 DCR is considered to be the maximum for iron heads and 92 octane fuel (MON + RON divided by 2). | ||
− | + | SCR vs. DCR vs. duration== | |
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: | 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: | ||
Line 41: | Line 32: | ||
*12.00.......68............8.017........................................................................................................ | *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. | 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]] | [[Category:Cylinder head]] |