Aluminum Supercharger Pulley for Mini Cooper S R53Available in two versions, 16% and 10% smaller pulley, designed for increasing the supercharger pressure up to 0. 4 bar and power up to 20 hp with significant torque increase. For 16% smaller pulley, upgraded injectors and intercooler is necessary and suggested for maximum performance. When combined with ECU Remapping, it is possible to achieve up to 40 horsepower increase with the smaller pulley compared to stock. The boost pressure with this pulley