Very true, and even moreso when comparing a forced-induction motor to a N/A one. For instance, you can really toss-out any correction factor when using nitrous oxide. You want to run at an effective altitude below sea level...? Use nitrous. Or even an efficient supercharger. It packs in a lot more O2 than any N/A engine could do given the same conditions...which is why turbos/blowers work so well at high altitudes.BrianK said:
I don't see O2 content of the ambient air mentioned much. This is a bigger problem in small dyno cells. You will lose power if the ventilation system isn't bringing fresh air to the engine. Hopefully this isn't generally a problem.
Some folks insist that SAE correction isn't 'correct' in all cases. Trying to compare a 50 degree run to a 95 degree run, even with correction, is probably more likely to introduce variability.