Copyright © 2005 Frank Jenis


Last updated 2005-10-22

Compression Ratio Calculator

This calculator lets you calculate compression ratios and then play "what-if" scenarios by changing variables. Click on any item for a complete description. The fields have been pre-loaded with values from my engine.

Cam Timing Info

Dimensional System

Cam Advertised Duration

Inches

Intake Valve Closes ABDC

Millimeters

Cylinder Bore:

Cylinder Stroke:

Number of Cylinders:

Deck Height:

Top Ring Height:

Piston Clearance:
Head Gasket Bore:

Head Gasket Compressed Thickness:

Head Chamber Volume

 cc

Piston Dish Volume:

 cc

Connecting Rod Length:

Elevation Above Sea Level

This section allows you to determine the effects of milling the heads or deck on compression ratio. Approximate the non circular portions of the combustion chamber using one or two chords.

Milling Depth:

Chord Depth 1:

Chord Depth 2:

Cylinder Volume:

Total Chamber Volume:

Nominal Static CR:

Nominal Trapped CR:
Engine Displacement: Engine Displacement:
Cylinder Cranking Pressure: