GFB Mach 2 Recirculating Plumb Back BOV
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GFB Mach 2 Recirculating Plumb Back BOV - Mitsubishi Evo (CD9A/CN9A/CP9A/CT9A/CZ4A) / Subaru WRX/STI (GC8) MY97-98 / Liberty GT (BM/BR) - 33mm
GFB's Mach 2 uses their proven TMS technology to return your turbo to peak boost up to 30% quicker than the factory diverter valve, without the drama of an open venting valve. It's a straightforward bolt-on upgrade for the Mitsubishi Evo and Subaru platforms, giving you sharper throttle response and reliable boost holding without touching your factory tune.
This listing covers the Mitsubishi Evo CD9A, CN9A, CP9A, CT9A and CZ4A chassis, along with the Subaru WRX and WRX STI GC8 (MY97-98), and the Liberty GT BM/BR. The 33mm Mach 2 is a direct factory replacement, requiring no adaptors or extra hardware.
Note: This unit is the 100% recirculating (plumb back) configuration, keeping performance without added blow off noise. GFB's atmosphere conversion kits, along with optional trumpet outlets, are sold separately if you want an audible venting sound.
Key Features
- 33mm valve size
- GFB TMS technology for faster boost recovery
- 100% recirculating (plumb back) configuration
- Direct bolt-on fitment — no adaptors required
- Effectively unlimited boost holding capacity
- Compatible with separate atmosphere conversion kits and trumpet outlets
Vehicle compatibility, OEM part numbers, and fitment notes are provided in the tabs above. Please confirm your vehicle's model year and configuration before ordering.
Not sure if this suits your build? Contact our team at sales@chicaneaustralia.com.au for expert advice.
Vehicle Compatibility
| Make | Model | Chassis | Engine |
|---|---|---|---|
| Mitsubishi | 3000GT/GTO | Z16A | 6G72 |
| Mitsubishi | Colt Ralliart | Z27A | 4G15 |
| Mitsubishi | Evo 1-3 | CD9A | 4G63 |
| Mitsubishi | Evo 4-6 | CN9A | 4G63 |
| Mitsubishi | Evo 4-6 | CP9A | 4G63 |
| Mitsubishi | Evo 7-9 | CT9A | 4G63 |
| Mitsubishi | Evo X | CZ4A | 4B11T |
| Mitsubishi | Lancer Ralliart | - | - |
| Subaru | Liberty GT | BM/BR | EJ255 |
| Subaru | WRX | GC8 | EJ20 |
| Subaru | WRX STI | GC8 | EJ207 |
Technical Specifications
| Spec | Value |
|---|---|
| Valve Diameter | 33 mm |
| Valve Configuration | 100% recirculating (plumb back) |
| Core Technology | GFB TMS (Turbo Management System) |
| Boost Holding Capacity | Unlimited (no turbo can produce enough pressure to open the valve) |
| Throttle Response Improvement | Up to 30% faster return to peak boost vs factory diverter valve |
| Atmosphere Venting Conversion | Convertible via hose plug or optional Atmosphere Conversion Kit (sold separately) |
No instructions available for this product.

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