One of the problems we commonly see with the bypass valve on the R53 Supercharged 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. A brand new BMW OEM part modified in house by 1320MINI.
