Each kit comes with a crank pulley only. Single belt conversion and underdrive pulleys (even with stock belt layouts) will require the purchase of separate belts, which are not included. However, Fluidampr does supply information in the instructions on which belt sizes work with each application.

Engine vibrations can be a dangerous situation when you're putting out a decent amount more power than your stock engine configuration. From the factory, the crank pulley helps with countering the vibrations, but can only do so much. The rubber they are made out of is not designed to handle too much and will age and degrade over time, ultimately failing.

Fluidampr resolves this issue by using viscous fluid, instead of rubber, to dampen engine vibrations. With a silicone-based fluid, it can adjust to the vibrations in real time and counter them at any RPM! The pulley is made of 3 pieces to achieve this: an outer housing, inner inertial ring, and the silicone fluid. The outer housing is built out of steel and precisely balanced to each application. The silicone fluid can retain its viscosity at extreme temperatures ranging from -4 degrees (F) to 300 degrees (F)! The inner inertia ring allows for some movement but is dampened by the silicone fluid which counters the incoming vibrations. Each Fluidampr pulley kit also provides timing marks for easy timing as well. This pulley is a great way to insure your modified Subaru WRX STI's engine is protected even for the highest horsepower builds.

Key Features:

• Helps smooth out dangerous torsional vibrations that can harm your engine if you're running a decent amount more power than from the factory.
• Unlike traditional rubber-based dampers, Fluidampr pulleys automatically adjust to vibrations in real time and counter them at any RPM!
• Allows for better operation and accuracy of the valvetrain and lowers risk of crank failure.
• Made of a precision steel outer housing, inner inertia ring, and viscous silicone-based fluid.
• The silicone-based fluid can handle extreme temperatures of -4 degrees (F) up to 300 degrees (F)!
• Underdriven pulleys will also help with reducing stress on other components as well, in addition to giving some power gains.
• "Single Belt Conversion" applications are designed for all out power, and thus only support a single belt going straight from the crank pulley to your alternator. No other accessories are supported on these applications.
• Finished in a corrosion resistant black zinc chromate for the ultimate protection.
• SFI 18.1 certified.
• Covered by a 1 year limited warranty.