The factory engine uses a bypass valve to bleed off the excess boost during throttle transitions. The factory unit is made from composite plastic which can be fragile on modified engines or in warmer climate. The Boost Bypass Valve Upgrade is an upgraded bypass valve that is made from alloy and uses a piston instead of a diaphragm.
Fits the following Cooper S models with the N14 engine:
2007-2010 R56 Cooper S Hatchback
2008-2010 R55 Cooper S CLUBMAN
2009-2010 R57 Cooper S Convertible
The most common complaint on the OEM solenoid valve is a split diaphragm preventing the valve from opening fully, or not at all. This doesn’t always result in a check engine light as the valve can still be blown open by the boost pressure. We have seen many valves with this problem. The other problem is that diaphragm retaining ring is made from very thin plastic that goes brittle with heat cycles, and eventually fails. This prevents the diaphragm from sealing with the same problems as mentioned above. This particular failure also results in the valve falling apart upon removal from the turbo, though in extreme cases bits of plastic can enter the turbo and destroy it. (see image below).
The alternative is a fully engineered solution offering both significantly improved reliability .Our valve is piston based , with no diaphragm to fail, and of all aluminium construction, it replaces the original unit with a pressure/vacuum operated piston valve that still also retains the desirable OEM ECU control over valve actuation. The valve has been proved on the VAG scene for many years. The spring is interchangeable for different levels of boost, and the solenoid is plug and play with the wiring harness which is included.
NOTE: Some states (like California) have ever tightening requirements for emissions testing and inspections. Always check your current state regulations on compliance for street use before you order.