The BMW S54 engine produces horsepower, however, all of this power is not fully achieved when the engine also has to drive other components such as air conditioning and power steering.
The Active Autowerke underdrive pulleys free up power from other belt driven sources. To help reduce this drag, Active Autowerke calculated and re-engineered the pulley dimensions that would reduce these power losses on your BMW motor. The finished product not only achieved this but it still maintained that level of reliability and efficiency.
What is redesigned is the water pump, alternator and power steering pulleys. What is not touched is the engine crankshaft pulley. By not altering the harmonic of the engine crankshaft, the engineers here at Active Autowerke wanted to achieve this through a redesign of just the auxiliary drives.
The end result is the unleashing of untapped power on the engine. An additional 10 rear wheel horsepower gain as measured on the in house Active Autowerke Mustang dyno.