The ATI Harmonic Balancer, Super Damper for the VQ35HR / VQ37VHR platforms offers the OEM fitment you are looking with patented and feature grooves for serpentine belts machined into the outer damper shell. The ATI Harmonic Balancer Super Damper for the Nissan 370Z, Infiniti G37, and 350Z HR is designed for high-performance, high-RPM engines that reach 6,000+ RPM's. The main reason we strongly suggest replacing your OEM crank pulley with an ATI Harmonic Balancer Super Damper for the Nissan 370Z, Infiniti G37, and 350Z HR is due to torsional vibration. When air/fuel mixture inside a cylinder is ignited in a high horsepower build, the combustion creates a torque spike to the crankshaft causing it to twist the crankshaft ahead of its normal rotation only to then rebound. This torsional vibration can ruin your motors bearings and crankshaft. The ATI Harmonic Balancer Super Damper is designed to eliminate the torsional vibration providing an opportunity for your high horsepower build to stay on the road for as long as possible. 

Fits wet sump oiling systems only. 4 percent underdrive. Its proven elastomer design is 2-in-1: a 4" diameter damper and a 7" diameter damper in two shells that bolt to the crank hub. Inner and outer shells are aluminum to contain the steel inertia weight. The inertia weight has eight computer-machined grooves to retain the proper durometer O-rings (installed at ATI and dyno tested for each application). O-ring life has been tested in Winston Cup competition over two million cycles and in drag racing engines for 10 years (exceeds SFI 18.1 specs). Units can be rebuilt by installing new O-rings. Shells have a black zinc chromate finish with computer-controlled, laser-engraved 360° timing marks.