The FA24 engine in the 2022+ WRX now uses an electronically controlled factory diverter in place of the pneumatic bypass valve found on all previous turbo Subaru engines. This is controlled by the ECU, and whilst it sounds like an advancement in technology, in some ways it is a step backwards. It may react to throttle closures faster than a pneumatic valve, but longevity and boost sealing is an issue with these types of valve because their valve mechanism is made entirely of moulded plastic. Importantly though, the factory electronic valve cannot open and close progressively - it's either open or shut, resulting in less than optimum throttle response and drivability.

• Solves boost leaking and reliability issues, whilst improving throttle response. Includes low-profile integrated solenoid to allow fitment in tight locations.