GFB Mach 2 Blow Off Valve Subaru WRX (GDB) STI (GDB/GRB/VAB) Forester XT (SG) Recirculating

GFB Mach 2 Recirculating Plumb Back BOV Blow Off Valve

GFB's Mach 2 is a direct bolt-on replacement for your factory bypass valve, built around GFB's proven TMS technology to help the engine return to peak boost up to 30% faster than the standard diverter valve. If you don't need the adjustable venting bias of the Respons or Deceptor Pro, the Mach 2 delivers the core boost holding and throttle response benefits in a simpler package for your Subaru WRX or STI.

This listing covers the recirculating (plumb back) version for the WRX 01-07, STI 01-21 (covering V1-V10 generations), and Forester XT 06-08. It installs as a straight swap for the factory valve with no extra adaptors or vehicle mods required. Atmosphere venting conversion kits are available separately if you want an audible blow off sound.

Note: Forester XT fitment requires the triangle flange BOV. Diamond flange equipped vehicles will need the T9500 model instead — check your factory BOV flange shape before ordering.

Key Features

• 100% recirculating (plumb back) configuration for factory-like operation
• GFB TMS technology for faster boost recovery and improved throttle response
• Holds boost pressure well beyond factory limits
• Direct bolt-on fitment — no adaptors or modification required
• Upgradeable to atmosphere venting via optional conversion kit or hose plug

Vehicle compatibility, OEM part numbers, and fitment notes are provided in the tabs above. Please confirm your Subaru's model year and BOV flange type before ordering.

Not sure if this valve suits your build? Contact our team at sales@chicaneaustralia.com.au for expert advice.