Compression is the ratio of total cylinder volume to the volume left over when the piston reaches top dead center.

What you do:

Choose a compression ratio that maximizes efficiency for your engine.

Factors to consider:

1. The higher the compression, the higher the combustion efficiency. This means more power.

2. The higher the compression ratio, the higher the temperature in the cylinder. Higher cylinder temperatures mean possible detonation of the fuel before the spark occurs. In real life, this could mean the fuel explodes while the piston is on its way up, causing engine damage. HiPerMath does not factor cylinder temperature in as engine damage, but cylinder temperature does factor in as decreased efficiency. Compression ratio alone will not cause inefficiency, but high compression and high boost from a turbocharger or supercharger will. HiPerMath factors these inefficiencies in as air temperature, which affects air density. See the supercharger and turbo charger pages to more information.

Real life note: In Hipermath, you set the compression ratio by entering a number. In real life, the compression ratio is determined by the stroke, cylinder height, deck height and combustion chamber size.