Uprated Rooster Racing Bypass Valve - Shipping rates apply at checkout

 The bypass valve is a very important part of the supercharger air flow system. It is a pretty much neglected part, as it is small and not very glamorous looking. However inside the valve is a rubber diaphragm and small conical spring that is vital to its function. Over time the spring weakens and when you change gear or simply close the throttle you may find a slight flutter or hesitation in the engine revs. This is known,  in the R53 Mini world as Yo-Yo. Now Mini did try an ECU tweak on the later models but even that is not going to work. It is a physical weakening that can not be rectified electronically. That fact alone is why I consider the bypass valve as something that should be replaced as part of keeping your engine running as it was meant to. So; here at Rooster Racing the spring is replaced by one made to specifications supplied to a UK manufacturer that is 25% stronger than standard. The 25% increase is chosen so that you will get a faster spring return whilst still opening correctly, should you have lower operating vacuum due to modified camshafts fitted. The diaphragm holder is then double sealed to prevent any air loss. Next the actual gap set on the butterfly part is closed down to as close to zero as possible. This is individually done to each valve whether it is race, track, or your road going car. This gives sharper throttle response and will keep the boost pressure  your supercharger set up makes going into the engine - where it matters. 

The Rooster Racing uprated bypass valve is made by using new aftermarket units 

PLEASE MAKE CONTACT IF YOU WOULD LIKE TO PAY CUSTOMS AND ANY TAXES BEFORE THE VALVE IS SENT. PAYING BEFORE WILL SPEED UP THE PROCESS.