When friction losses are subtracted from the IMEP, the result is the brake mean effective pressure (BMEP).

Since the range of maximum brake mean effective pressures for good engine designs is well established, we now have a displacement-independent measure of the torque-producing capacity of an engine design – a specific torque of sorts.

Mean effective pressure is also useful for initial design calculations; that is, given a torque, standard MEP values can be used to estimate the required engine displacement.

[2] Brake mean effective pressure (BMEP) is calculated from measured dynamometer torque.

In our example, the engine puts out 159 N·m of torque at 3600 min−1 (=60 s−1): Thus: As piston engines usually have their maximum torque at a lower rotating speed than the maximum power output, the BMEP is lower at full power (at higher rotating speed).