GrimmSpeed V2 Bypass Valve - Red - 2004-2021 Subaru STI / 2002-2007 WRX
GrimmSpeed V2 Bypass Valve - Red - 2004-2021 Subaru STI / 2002-2007 WRX
GrimmSpeed
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Grimmspeed's Version 2 Bypass Valve
During testing of stock bypass valves, GrimmSpeed observed repeated internal leakage at low boost levels, prompting the development of an extremely durable bypass valve. GrimmSpeed aimed to create a bypass valve capable of handling double the pressure of the stock unit while maintaining a stylish appearance. These valves stand out and are guaranteed to endure the test of time compared to stock and cheap aftermarket alternatives.
Material and Design:
Crafted from CNC-machined billet 6061 aluminum alloy, the valve body and base are anodized for corrosion resistance and a stunning appearance. Unlike stock and aftermarket alternatives, GrimmSpeed Bypass Valves feature a machined brass piston for anti-corrosion and low thermal expansion. The 38mm piston and sealing ring facilitate rapid pressure release, crucial for high boost applications. The precisely-tuned steel spring eliminates the need for tuning, and Buna-N O-rings resist degradation from fuel and oil exposure. A swivel fitting ensures easy installation and accommodates custom setups. The GrimmSpeed signature branding badge signifies your choice for top-tier valve performance. The 15-21 WRX (FA) unit is designed with a compact footprint, maintaining the 38mm piston while streamlining the valve's overall size for improved working space. The GrimmSpeed Bypass Valve brings noticeable crispness and sound changes through the intake, ensuring a quick boost build-up over OEM alternatives.

New for Version 2:
- Redesigned Internal Piston: Eliminates potential failure points seen in the V1 design.
- Adjusted Spring Tension: Better suited for operating environments after extensive testing.
- Improved CNC Milling Finish: Updated main body design for enhanced aesthetics.
- Lightweight Hard Aluminum Piston: Replaces internal brass piston for improved valve response.
- Removal of Inspection Port: Quality control feature no longer required with the new design.
Key Features:
- Color: Red
- CNC-Machined 6061 Aluminum: Precision-engineered for strength and durability.
- Corrosion-Resistant Anodized Finish: Red anodized finish for a stylish appearance and corrosion resistance.
- Oversized 38mm Aluminum Piston: Superior flow for quick pressure release.
- Precision-Tuned Steel Spring: Ensures long life and optimal performance.
- Swivel Air Fitting: Facilitates easy installation and accommodates custom setups.
- Single Dovetail O-Ring Grooves: Equipped with Buna-N O-rings for excellent oil resistance, retention, and leak-free operation.
- No Tuning or Adjustment Required: Hassle-free operation without the need for tuning.
Fitments:
- 2004-2021 Subaru STI
- 2002-2007 Subaru WRX
- 2006-2008 Subaru Forester XT
- 2004-2005 Subaru Forester XT (with STI-Style TMIC)
- 2004-2006 Subaru Baja XT (with STI-Style TMIC)
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Grimmspeed's Version 2 Bypass Valve
During testing of stock bypass valves, GrimmSpeed observed repeated internal leakage at low boost levels, prompting the development of an extremely durable bypass valve. GrimmSpeed aimed to create a bypass valve capable of handling double the pressure of the stock unit while maintaining a stylish appearance. These valves stand out and are guaranteed to endure the test of time compared to stock and cheap aftermarket alternatives.
Material and Design:
Crafted from CNC-machined billet 6061 aluminum alloy, the valve body and base are anodized for corrosion resistance and a stunning appearance. Unlike stock and aftermarket alternatives, GrimmSpeed Bypass Valves feature a machined brass piston for anti-corrosion and low thermal expansion. The 38mm piston and sealing ring facilitate rapid pressure release, crucial for high boost applications. The precisely-tuned steel spring eliminates the need for tuning, and Buna-N O-rings resist degradation from fuel and oil exposure. A swivel fitting ensures easy installation and accommodates custom setups. The GrimmSpeed signature branding badge signifies your choice for top-tier valve performance. The 15-21 WRX (FA) unit is designed with a compact footprint, maintaining the 38mm piston while streamlining the valve's overall size for improved working space. The GrimmSpeed Bypass Valve brings noticeable crispness and sound changes through the intake, ensuring a quick boost build-up over OEM alternatives.

New for Version 2:
- Redesigned Internal Piston: Eliminates potential failure points seen in the V1 design.
- Adjusted Spring Tension: Better suited for operating environments after extensive testing.
- Improved CNC Milling Finish: Updated main body design for enhanced aesthetics.
- Lightweight Hard Aluminum Piston: Replaces internal brass piston for improved valve response.
- Removal of Inspection Port: Quality control feature no longer required with the new design.
Key Features:
- Color: Red
- CNC-Machined 6061 Aluminum: Precision-engineered for strength and durability.
- Corrosion-Resistant Anodized Finish: Red anodized finish for a stylish appearance and corrosion resistance.
- Oversized 38mm Aluminum Piston: Superior flow for quick pressure release.
- Precision-Tuned Steel Spring: Ensures long life and optimal performance.
- Swivel Air Fitting: Facilitates easy installation and accommodates custom setups.
- Single Dovetail O-Ring Grooves: Equipped with Buna-N O-rings for excellent oil resistance, retention, and leak-free operation.
- No Tuning or Adjustment Required: Hassle-free operation without the need for tuning.
Fitments:
- 2004-2021 Subaru STI
- 2002-2007 Subaru WRX
- 2006-2008 Subaru Forester XT
- 2004-2005 Subaru Forester XT (with STI-Style TMIC)
- 2004-2006 Subaru Baja XT (with STI-Style TMIC)
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