Brake Mean Effective Pressure
BMEP is a normalized measure of an engine’s ability to do work, independent of displacement or speed, making it useful for comparing engines of different sizes. It’s calculated as BMEP = (P × nr × 120) / (Vd × N), where P is brake power (kW), Vd is total displacement (liters), N is engine speed (RPM), and nr is the number of crankshaft revolutions per power stroke (2 for a four-stroke engine, 1 for a two-stroke).
Higher BMEP indicates a more highly tuned or efficient engine relative to its size — well-tuned naturally aspirated gasoline engines typically reach roughly 1,000–1,300 kPa, while turbocharged and racing engines can exceed that considerably. This is a standard automotive/mechanical engineering reference calculation for general educational use.