BOFI Racing 150mm Supercharger Overlay Pulley for Mazda MX-5 NA NB
The 150mm supercharger overlay pulley overdrives the supercharger to spin it faster and make more boost. The diameter is increased from 130mm to 150mm, increasing the RPM of the supercharger to 16,615 RPM at the 7,200 redline. Increasing the size of the crank pulley means the larger supercharger pulley can be retained, reducing belt slip.
Your Mazda MX-5 will require re-tuning to extract maximum performance from the increase in boost and to prevent it from knocking.
To make the most of the overlay pulley we recommend installing a larger 230mm intercooler to keep intake temperatures down and make maximum power. The overlay bolts straight over the existing crank pulley from 94-05 cars that have a flat-faced black steel pulley. If your pulley is a brown cast-iron pulley with a raised mounting surface, it can be swapped out for the black steel pulley.