Volumetric Efficiency

A strong VE number basically means the engine has both a well matched and "working" intact tract, and a cam that lets the exhaust blowdown event work to completely empty the cylinder. Intake charge leaving through the exhaust is as bad as exhaust gasses being left in the cylinder. The problem is like Andy said... the measuring systems are potential issues, and there is no correlation to performance of the engine in a chassis. So fun number to look at, good number to "nail", but not worth much aside from validation of other decisions.