Use this dynamic compression calculator to quickly determine the compression ratio of your engine based on entered parameters.
Dynamic Compression Calculator
How It Works
This calculator determines the dynamic compression ratio (CR) of an engine, which is an important factor in understanding an engine’s performance. The dynamic CR is different from the static CR because it takes into account the closing point of the intake valve.
To use the calculator, simply enter the bore diameter, stroke length, combustion chamber volume, head gasket thickness, piston dome volume, and deck clearance in their respective fields. After entering the values, click “Calculate” to view the dynamic CR.
The dynamic CR is calculated using the following formula:
CR = ((Swept Volume + Clearance Volume) - Compressed Volume) / Compressed Volume
where,
- Swept Volume is the volume displaced by the piston as it moves between the top and bottom of the stroke.
- Clearance Volume is the sum of the volumes of the combustion chamber, piston dish/dome, gasket and deck clearance.
- Compressed Volume is the volume of the air-fuel mixture when the piston is at top dead center.
Limitations
This calculator does not account for dynamic factors like gas temperatures and pressures, and assumes all measurements are perfectly accurate. Actual dynamic CR may vary based on a number of other factors, and this should be considered an approximation.