Our specially designed and engineered S85 underdrive pulley kit is a great addition to the M5/M6. This is done by improving power through reducing parasitic drag on the engine from slowing the speed of the alternator, water pump and AC compressor components. Hp Gains are approx 10-20hp depending on condition of car, climate, and other preformance products.
For maximum performance we also suggest pairing our full exhaust system with our specially designed performance software
-CNC hard anodized S85 crank pulley. Precise and measured belt groves and bolt holes.
-Power steering & AC belt
CAN NOT BE COMBINED WITH SUPERCHARGER SYSTEM!