From £105 KAVS Motorsport reduced diameter supercharger pulley is a proven and affordable method of producing reliable power gains on the R53 MINI Cooper S. Offered in a variety of reduced diameters compared to the BMW original (11%, 13.2%, 15%, 17% 19%) the smaller diameter pulley spins the supercharger up faster, enabling it to pump more air and produce more boost, which turn raises torque and power output. The KMT pulleys are your first stop on the path to serious power from your R53 MINI Cooper S and they work particularly well in conjunction with an intercooler upgrade. For sizing reference information, the 218 bhp R53 MINI Cooper S GP model ran an 11% reduced pulley compared with standard (in conjunction with a larger intercooler.) Produced from superior quality material from competitor brands and features a central reel with a double edged design to reduce supercharger drive belt wear when compared to the OEM BMW item. Every KMT pulley is also subject to strict quality control tests which adhere to the high ISO 9001:2008 and ISO 14001:2004 standards. If you would like the full kit of everything needed to bolt right onto your car, please click the 'Belt, and Spark Plug' tick boxes on the right of the screen and 1320 will send you the correct length belt matched for your pulley size, plus a set of colder running plugs to cope with the higher boost pressures. Optimum Bypass Valve for the R53 MINI Cooper S Why should you consider an optimized bypass valve? One of the problems we commonly see with the bypass valve on the R53 MINI Cooper S is that the butterfly doesn’t close all the way due to a weak or broken spring, therefore you’ll be losing precious boost at wide open throttle. 1320 can supply and fit you a new modified OEM BMW bypass valve which is adjusted to close fully ensuring that you will now see maximum boost at wide open throttle.