2015 BMW M3 Dyno Reveals Just How Much Horsepower It Really Makes

Some brands are known for underrating their cars’ horsepower, just as others are known for overrating their cars’ gas mileage. So where does BMW land on the spectrum, or more specifically, where does the 2015 M3 land?

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With official ratings of 425 horsepower and 406 pound-feet of torque, you’d expect an at-the-wheels rating of somewhere around 360 horsepower and 345 pound-feet with typical driveline losses.

The figures from Motor Trend’s test of the 2015 BMW M3 on K&N Engineering’s dyno put BMW and the new M3 firmly in the underrated camp (or the highly efficient power-transfer camp): the dyno results showed 379 horsepower and 378 pound-feet of torque. Hit the link to see the dyno graphs and other details.

The nearly symmetrical result is about 5 percent above what might be expected, so it’s not a tremendous underrating, and given the vagaries of results from one dynamometer to the next, it could simply be a spot-on result, matching rated horsepower at the flywheel identically.