The factory accessory drive on the BMW E9X M3, E60 M5, and E63 M6 runs the alternator, power steering, and water pump at engine speed — spinning them harder than necessary and consuming horsepower from the S65 or S85 in the process. The Macht Schnell Performance Underdrive Pulleys use a DualDrive design to slow accessory rotation relative to crank speed, recovering that parasitic drag as usable wheel horsepower and torque.
CNC-machined from 6061-T6 aerospace aluminum and T3 hard-anodized, these pulleys deliver 9–14 hp / 7–9 lb-ft on the E9X M3 and 18–20 hp / 16–20 lb-ft on M5/M6 models with zero impact on crank harmonics or balancing. Cooling and alternator output remain within factory spec at all operating conditions. New belts are included for a complete bolt-on installation. E9X M3 note: select the 06/08+ variant if your power steering belt is double-sided.
Brand: Macht Schnell
Fitment: BMW E9X M3 (2008+), E60 M5 (2006–2010), E63 M6 (2006–2010)
Engine: S65B40 (M3), S85B50 (M5/M6)
Material: 6061-T6 aerospace aluminum, T3 hard-anodized
Design: DualDrive — reduces accessory rotation relative to crank speed
Power gain (M3): 9–14 hp / 7–9 lb-ft torque
Power gain (M5/M6): 18–20 hp / 16–20 lb-ft torque
Cooling and alternator output: Within factory spec
Crank harmonics: Unaffected
Includes: New drive belts
