Within some industry circles, it's quite known that the German auto makers underrate the power output of their engines. There are many theories as to why this is done. Some refer to it as "over-engineering" while others may consider it a marketing tactic. For most enthusiasts, it can be a bragging point, but for the owner of this brand new 2012 328i sedan it seems the intention was to establish a baseline for future performance tuning projects.
Equipped with BMW's new twinpower twin-scroll turbo 2.0-liter 4-cylinder N20 engine, BMW specifies its power rating in North America at 240 bhp (179 kW / 243 PS) and 260 lb-ft (350 Nm).
Using an EAS (European Auto Source) Dynojet 224xLC, the 328i produced 226 hp (169 kW) and 230 lb-ft (312 Nm) torque measured at the wheels with 91 octane gasoline. This equates to a crankshaft horsepower rating of approximately 265-272 hp (198-203 kW) / 270-277 lb-ft (366-376 Nm) torque - an increase of 25-32hp (19-24 kW) and 15-22lb-ft (20-30) over the official figures. This calculation assumes a 15-17% drivetrain loss.
The same N20 engine in the 2012 BMW Z4 was also found to have increased numbers although slightly higher than the 328i seen here.