Originally posted by charro
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How did they derive the engine output? What the engine makes is different to what is measured at the wheels, with the difference due to drivetrain loss. Drivetrain loss is difficult to measure, but you would normally start with the manufacturers stated output and compare to the measured output at the wheels. At a recent dyno day, a Stock Golf 7 R made 173Kw at the wheels. Assuming 206 at the engine, so looking at about 16% drivetrain loss, which pretty closely matches the "15%" rule. AWDs do have a higher rate of loss, but I believe the dynos test the Golf R in FWD mode only (no loss of traction, so no need to send power to the rear), so 15-16% is expected. 173 to 221 is nearly 22% loss.
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