Fits E63, C63, CLS63, CL63, S63, SLS63

The Ultimate Performance and Design (UPD) M156 Underdrive, lightweight and strengthened crank pulley is designed to increase power and torque by slowing down the rotation of all the engines accessories.

By providing a much lighter crank pulley made of billet aluminumb/ steel verses low cost cast iron used on the stock crank pulley: Your throttle response, engine performance and MPG will be improved and turbo will rev much quicker.

Using latest design and finite analyses software, plus real world testing, UPD is able to design a billet underdrive pulley that greatly out performs the OEM cast iron crank pulley and much higher quality, precision balanced CNC performance crank pulley.

OEM crank pulley weight is 11.2 lbs VS the UPD billet -steel underdriven pulley.

Throttle response is improved.