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`CR = ( V_1 + V_2 )/ V_2 `

Enter a value for all fields

The **Compression Ratio **calculator computes* Single Engine Cylinder* the compression ratio (CR) of a combustion engine cylinder.

**INSTRUCTIONS:** Choose your volume units (default is cubic inches), and enter the following:

- (
**V**) Total volume of the cylinder._{1} - (
**V**) Combustion chamber volume (aka clearance or compression volume)_{2}

**Compression Ratio:** The calculator returns the Compression Ratio (CR).

The formula for Compression Ratio is:

CR = (V_{1} + V_{2})/V_{2}

where:

- CR = Compression Ratio
- V
_{1}= Total Volume of Cylinder - V
_{2}= Combustion Chamber Volume

**Cylinder Bore Diameter**based on the engine displacement, number of cylinders and the stroke length.**Bore Stroke Ratio**based on the diameter of the bore and the length of the stroke.**Combustion Ratio**base on the minimum and maximum displacements of the cylinder at the beginning (1-Induction) and compressed (3-Power) portions of the combustion cycle**Displacement Ratio**based on the volumes at the beginning and end of the stroke.**Rod and Stroke Length Ratio**base on the two lengths.**Stroke Length**based on the total engine displacement, number of cylinders and the bore.**Piston Position**based on the crank angle, crank radius, and rod length.**Total Volume (displacement) of a Combustion Engine**based on the bore, stroke and number of cylinders.**Volume (displacement) of a Engine Cylinder**based on the bore and stroke.**Volume (displacement) of an Engine with an Overbore**based on the stroke, bore, overbore and number of cylinders.**Equivalent Volume of a Rotary Engine**based on the swept volume and number of pistons.**Compressed Volume of a Cylinder**when the piston is at the end of the stroke and the chamber is at its smallest (and most compressed) volume, based on the chamber, deck, crevice, chamfer, gasket, valve relief and dome/dish volumes. This is the second volume (V2) in the Compression Ratio**calculation.****Volume of a Gasket**based on the inner and outer diameters and the gasket's thickness.**Volume of a Cylinder Deck**based on the deck height and the bore.**Volume of a Cylinder Crevice**based on the piston diameter, cylinder bore and the crevice height.**Volume of a Cylinder Chamfer**based on the cylinder diameter and the chamfer height and width.**Piston Speed (mean) based on stroke length and RPMs.****Max Piston Speed based on stroke length and RPMs****RPMs based on desired piston speed and stroke length**.

- Camber Angle
- Camber Offset
- Breakover angle - Ground clearance between axles
- Approach angle - Ground clearance in front of or behind vehicle.
**Belt Length****Belt Speed**.**Pulley RPMs****2nd Pulley RPMs****2nd Pulley Diameter****RPM of 4th pulley on three shafts****2nd Gear RPM**