Bypass Valve

The GrimmSpeed Bypass Valve in Red is engineered specifically for the FA20DIT engine found in the 2015-2021 Subaru WRX. This unit directly replaces the factory recirculating bypass valve, offering enhanced performance and protection for the turbocharger. Its recirculating design ensures that compressor-side pressure is routed back into the intake ahead of the turbocharger during throttle-off events. This action effectively prevents compressor surge without venting metered air to the atmosphere, which is crucial for maintaining accurate MAF sensor readings and avoiding lean stumble or idle hunting on MAF-based air management systems like the FA20DIT. Constructed from billet 6061 aluminum alloy with a striking red anodized finish, this bypass valve is designed to handle boost pressures beyond factory levels, making it suitable for modified FA20DIT builds. Installation is a straightforward bolt-in procedure, utilizing the factory mounting hardware and vacuum reference line at the original bypass valve location. No charge pipe modification, additional fittings, or re-routing are necessary for a complete installation. It is important to note that this bypass valve is recirculating only and is not an atmospheric blow-off valve. It is not compatible with fully atmospheric BOV applications on MAF-based FA20DIT engines.