The compression ratio isn’t just a number: it’s one of the greatest determining factors in engine building. Compression ratio determines the type of fuel, how much boost, and has a significant ...

Engine Compression Atmospheric pressure at sea level is approximately 14.7 psi. A 9:1 compression ratio cylinder is compressing the air and fuel mixture to about 132 psi at sea level (9x14.7=132.3).

From our rather limited research, it appears that building a performance street engine that combines a decent-duration camshaft with enough static compression ratio to create 175 to 190 psi, will ...

A compression test reveals the condition of your engine's valves, its valve seats, and piston rings and whether these parts are wearing evenly. Healthy engines should have compression over 100 psi ...