Proper overlap formula?
07-24-2008, 10:00 PM
#2
to calculate a cam's overlap you add the intake duration to the exhaust duration, divide that sum by 4, subtracting the LSA figure, finally multiplying the result by 2.
Example #1: (Comp Cams 224/236 cam)
Intake duration.....: 276 (@ .006)
Exhaust duration....: 288 (@ .006)
....................:===
=========total......: 564
Divide by 4.........: 564 / 4 = 141
Subtract LSA........: 141 - 112 = 29
Multiply result by 2: 29 * 2 = 58 degrees of overlap
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*
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Example #2: (a generic Turbo cam)
Intake duration.....: 218 (@ .006)
Exhaust duration....: 212 (@ .006)
....................:===
=========total......: 430
Divide by 4.........: 430 / 4 = 107.5
Subtract LSA........: 107.5 - 114 = -6.5
Multiply result by 2: -6.5 * 2 = -13 degrees of overlap
Example #1: (Comp Cams 224/236 cam)
Intake duration.....: 276 (@ .006)
Exhaust duration....: 288 (@ .006)
....................:===
=========total......: 564
Divide by 4.........: 564 / 4 = 141
Subtract LSA........: 141 - 112 = 29
Multiply result by 2: 29 * 2 = 58 degrees of overlap
*
*
*
Example #2: (a generic Turbo cam)
Intake duration.....: 218 (@ .006)
Exhaust duration....: 212 (@ .006)
....................:===
=========total......: 430
Divide by 4.........: 430 / 4 = 107.5
Subtract LSA........: 107.5 - 114 = -6.5
Multiply result by 2: -6.5 * 2 = -13 degrees of overlap
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