ACT XACT ProLite flywheels are ideal for road race Subaru WRX STIs that require a very quick throttle response and instant acceleration. Most stock flywheels are heavy cast iron parts designed for optimum street driveability by soaking up some of the power from the engine and putting it in storage in the form of inertia. Although this may be important for transporting the groceries, this driveability comes at the expense of engine response and acceleration.
Light weight flywheels keep less inertia in storage but the lighter rotating mass provides significantly improved engine response and acceleration characteristics. Until now, most aftermarket flywheels for Subaru WRX STIs presented certain undesirable concessions to the user. Many are too light or fragile for the application, others have reliability issues and all are very expensive.
Finally, ACT offers excatly what performance enthusiasts need: all the benefits of a premium quality light weight flywheel at an affordable price.
ACT XACT flywheels are certified by ACT to meet SFI Spec. 1.1. This makes XACT Flywheels legal for competition when SFI Spec. 1.1 is required or recommended. XACT flywheels come complete with official SFI sticker and serial number as required for certification.
ACT ProLite Flywheel Key Features:
- Preferred for road racing.
- Very quick throttle response and acceleration.
- Extremely light (as low as 8.4 pounds!), with minimal rotational inertia.
- Made from hot forged chrome-moly steel for extreme strength.
- CAD designed and dynamically computer balanced.
- 1 year limited warranty.
Note: If you plan on using your Subaru WRX STI for normal street use or drag racing, you may prefer the StreetLite flywheel. For straight-line acceleration, a higher moment of inertia is more desirable because it keeps the engine from slowing itself down too quickly. The ProLite flywheel is made for road racing, where a low moment of rotational inertia will lead to better lap times.
