We might be covering ground that's well trampled for many, but the static compression ratio of an engine is simple to understand: it's all the volume of a cylinder above the compression ring at Bottom ...

Here's the equipment for the two cc'ing operations. Arrow indicates rubber Oring. Syringe eases removal of alcohol. Determining the compression ratio of an automobile engine is no easy task.

Diesel engines are different from gas engines in numerous ways, including their use of high compression ratios. Here's why that is and what it means.