Thread: M3 dyno
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      02-22-2013, 03:04 PM   #5
CanAutM3
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"Wheel torque" as expressed here is a number that does not exist in real life. The actual wheel torque should be multiplied by the gear and final drive ratios.

The torque numbers presented on dyno charts are simply calculated from the wheel horsepower and engine RPM to represent an "equivalent" flywheel torque number. The real flywheel torque number is actually higher as it does not see powertrain losses.

Either you show wheel torque multiplied by the gear ratio or flywheel torque without the drivetrain losses (which you cannot measure wihout removing the engine). Anything else is a fictive number.

Torque numbers as presented on most chassis dyno charts should only be used as a reference to get an idea of the shape of the torque curve.

I would not dwell too long on the absolute power numbers, even less so on the absolute torque values of the dyno runs. Rather focus on the relative before and after runs to see how much gain you are getting from mods.

Last edited by CanAutM3; 02-25-2013 at 09:54 AM.