Description
Upgrade your vehicle’s performance with the GFB light-weight under-drive pulley kit, designed to enhance throttle response and power output! Crafted with precision on state-of-the-art Multi-Axis CNC machines from premium 6061-T6 aluminum billet, these pulleys are substantially lighter than factory steel counterparts, with weight savings averaging around 2kg. The GFB 300ZX pulley goes even further, slashing over 7kg in weight. This substantial reduction in rotating inertia accelerates your engine faster, akin to the impact of a lightened flywheel, particularly noticeable in the lower RPM range before turbo spool-up.
Achieve additional power gains through under-driving by reducing the size of the crank pulley. This action slows down accessories, decreasing the load, especially at high RPM. Rest assured, driven accessories operate at peak efficiency between idle and 1400RPM, ensuring no compromise to battery charging or power steering. As RPM increases, the under-drive ratio minimizes wasted power, resulting in significant power gains without boosting pressure.
Enter the Atomic Boost Controller, a game-changer tested on an MY02 Subaru WRX with a turbo-back exhaust. In back-to-back tests against the factory controller, the Atomic exhibited substantial gains, providing as much as 18kW (23.4hp) at the wheels! This powerful controller allows boost to rise earlier than the factory counterpart, delivering superior acceleration from as low as 1700RPM. Ideal for MY01-02 WRX models, the Atomic or Reactor boost controller transforms your driving experience without exceeding the factory peak boost level.
For rotary enthusiasts, our alternator pulley replacement caters to early 12A and 13B rotaries up to series 5 RX-7 (vehicles with 15 mm alternator shaft). This pulley introduces a second v-belt for enhanced reliability on high-revving engines, without altering the alternator’s drive ratio. Available in Red, Blue, Black, and Silver, this pulley eliminates belt slip, shares the load between two belts, and provides a backup belt in case of failure.
Upgrade your vehicle’s performance with GFB’s innovative solutions – the best “bang-for-your-buck” modifications you can make!

