This Blow off or Atmospheric Dump valve is for the Mini Countryman R60/R58 Cooper S/Peugeot 208 Gti/Peugeot RCZ (156 and 200THP) that have the electronically controlled bypass valves (Cooper S models ). It is either recommended where the boost pressure has been increased by an ECU software upgrade or simply for those wanting a loud Blow off sound or simply as a solution to the many failures that have occurred.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 (see image below). The other problem is that diaphragm retaining ring is made from very thin plastic tha.
