We have a chassis dyno that we use to tune, On motors that we have engine dynoed and then chassis dynoed depending on the converter have been from 21-28% loss difference. With a stick it has been 18-20% loss This is not something i live by but just reference. The chassis dyno should only be for tuning and not see what THE NUMBER IS. I dont care what the number is I tune to see if there is any more. We also determine if converter is right for the outcome.