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GrimmSpeed Bypass Valves (WRX / STi / Legacy GT) V2 w/ No Tuning Required

GrimmSpeed Bypass Valves (WRX / STi / Legacy GT) V2 w/ No Tuning Required

The GrimmSpeed line of Bypass Valves have been a highly sought-after product. Due to the intensive assembly process, it has been hard to keep them on the shelves, which in turn causes frustration among our customers. To address this issue, our team has worked diligently to redesign the BPV to make the assembly process more efficient, while also improving performance and overall reliability of the valves.

Grimmspeed designed the valve body and base for each fitment from billet 6061 aluminum alloy, then anodized them in black or red to match our other existing product offerings. Doing this provided corrosion resistance, and a brilliant appearance. This second iteration of our Bypass Valves come equipped with a massive 38mm diameter aluminum piston to quickly dump pressure, an important feature for to maintain leak-free operation and ensuring proper operation of a forced-induction platform. Our valves include Buna-N O-rings for resistance to abrasion and any fluids that may find themselves into your intake system. A swivel fitting accommodates custom setups and allows for easy installation.

Best of all, there is no tuning required for any of our bypass valves! With the GrimmSpeed Bypass Valve installed, there is a noticeable change in sound and crispness through the intake, and the car builds boost much more quickly than with the leak-prone OEM version. The STI unit reuses the recirculating elbow from the factory BPV, ensuring precise alignment and a perfect fit, making for a total plug-and-play package.


  • Redesigned the internal piston to eliminate the potential failure points we saw in our V1 design.
  • Adjusted tension of the internal spring to better suit the operating environments we’ve seen after further testing and development.
  • Updated the design of the main body for a better CNC milling finish.
  • Exchanged the internal brass piston from V1 for a lighter weight hard aluminum piston, resulting in better valve response.
  • Removed the inspection port which was primarily used for quality control, but it is not required with the new design.


  • CNC-Machined 6061 Aluminum 
  • Corrosion resistant anodized finish, available in both red and black 
  • Oversized 38mm anodized aluminum piston for superior flow 
  • Swivel air fitting to aid in install and for accommodating custom setups
  • No tuning or adjustment required 
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