I'm really curious how wheel torque is measured on a dyno like that. Basically, torque is multiplied through the gear ratios, while HP is lost. There may be some torque loss through deflection of shafts, etc, but still gearing multiplies torque.
The torque sent to wheels would be the same as torque on the axle, and that is equal to engine torque X trans ratio X final drive ratio. If a car make 200 lb-ft, has a 3.5:1 1st gear ratio, and a 4:1 final drive ratio, that car puts 2800 lb-ft to the axle. I've seen instrumented test data (torque meters on the wheels), I can verify this what happens.
I know dyno runs are usually made in what ever gear is closest to 1:1, but still, the dyno operator would have to know all the appropriate gear ratios (do they?) to accurately calculate what the engine is putting out.
Am I missing something???
