This calculation will determine the advertised intake valve closing point needed for calculating dynamic compression ratio, DCR. Sometimes cam companies only publish 0.050" valve timing events. The Intake valve closing event ABDC is crucial in determining DCR for your engine. Most people use the 0.050" numbers in the calculation resulting in an incorrect DCR result.

To use this calculator you need to know the cam's advertised intake duration, 0.050" intake duration, and the Intake valve closing point from the cam card. If you don't have all this information you may be able to calculate it from the Cam Events Calculator.

Cam Name Intake Advertised Duration (°) Intake 0.050" Duration (°) Intake Valve closing point @ 0.050". (ABDC °) Calculator requires a subscription.