Manufacturers sometimes underrate their own showroom cars, providing incorrect engine power and torque figures. Automotive publication Inside Line in the US recently got their hands on a new BMW 1 M Coupe and strapped it to a chassis dyno to see how the figures shaped up.

Power figures from a chassis dyno are more often than not around 20-25 percent less than factory figures. This is due to manufacturers measuring the levels straight from the crank of the engine. On a dyno, however, power is lost through the driveline. So if a car has 100kW at the engine, in a normal two-wheel drive car, you would expect figures of around 70-80kW at the wheels.

In standard trim, BMW says the 3.0-litre turbocharged straight-six engine in the 1 M produces 250kW (335hp) of power and 450Nm of torque (500Nm on overboost) at the engine. During this dyno test however, the car produced 331hp (247kW) at the wheels, which suggests there's even more power available from the engine. Torque was also surprising compared with the factory figures, 362lb/ft (490Nm).

Take a look at the video below to see the tests.