Volumetric Efficiency

VE is useful for comparing different engines but only if the engines are all tested on the same dyno or only if the numbers are trusted. It isn't that easy to get accurate airflow numbers so I don't really trust any VE numbers I see published. The air turbines that are used on most dyno engines don't seem to be all that accurate. One way to check is to look at the AF ratio generated by dividing the air flow by the fuel flow. On most dynos that number is significantly different than the AF ratio which the wide band is reading. So that tells you that something else is going on. Either the wide band is wrong, or the air flow meter is wrong, or the fuel flow meter is wrong. They can't all be correct if they don't provide the same number. Figuring out which is wrong can be a difficult task though..........