Compression

Dyno testing is about maximum and maximizing power where it’s making the power.
That might be what is most important to you when dyno testing and much of the time that is what my customer wants . But that isn't always the case for me or my customers at the dyno. As an example sometimes trading a few hp at the maximum in order to increase power somewhere else is beneficial for the customer. There is a lot of other data collected with the power numbers and sometimes that data is more important than the power numbers. Another example is in circle track racing where driveabilty is given precedent over maximum power. In enduro racing the amount of fuel used vs maximum power is a consideration so we might be looking at brake specific fuel consumption and changes to improve that. I have used the dyno to look at oil pressure and changes that affect oil pressure.
Somtimes I swear all my dyno is good for is finding oil leaks. If you have dyno you're chuckling right now.