GrimmSpeed V2 Bypass Valve Subaru STI 2004-2021 / WRX 2002-2007 – Black | 126032BLK GrimmSpeed

The days of sacrificing performance to leaky BPVs are over, because the long-awaited GrimmSpeed Bypass Valves are here!

This is the newest version 2 Grimmspeed bypass valve. The previous models had some leaking issues, and these are solved. Tested up to 100 psi!

Fitment Information:

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)

Features:

• Color: Black
• CNC-Machined 6061 Aluminum
• Corrosion resistant anodized black finish
• Oversized 38mm anodized aluminum piston for superior flow
• Precision-tuned steel spring for long life
• Swivel air fitting to aid in install and for accommodating custom setups
• Single dovetail O-ring grooves with Buna-N O-rings for great oil resistance, retention, and leak free operation
• No tuning or adjustment required

What’s New for Version 2?

• Redesigned the internal piston to eliminate the potential failure points that were seen in the V1 design
• Adjusted tension of the internal spring to better suit the operating environments 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

Our passion for building the most robust, best-performing parts on the market has driven us to create the finest version of one of the hardest-working parts of your vehicle’s turbo system.

Performance

In testing of stock bypass valves, we saw repeated internal leakage at boost levels as low as 8psi in the FA20 and 19psi in the EJ variant. As always the case with GrimmSpeed Products, we focus on form AND function, and these units are no exception. We aimed to create an extremely durable bypass valve that could hold double the pressure of the stock unit, while still being a stylish part that compliments the other GrimmSpeed Parts under your hood.

Material and Design

We started the ground-up design with the valve body and base for each popular fitment. Both are CNC-machined out of billet 6061 aluminum alloy for its strength and light-weight. They are then anodized to give them a brilliant appearance, provide corrosion resistance and match other GrimmSpeed offerings. Compared to the stock cast unit on the EJ STI and plastic construction on both the 08-14 and 15-21 WRX platforms, GrimmSpeed Bypass Valves not only stand out, but are guaranteed to stand the test of time.

For the internal components of the valve, we chose to utilize a machined brass piston for its anti-corrosion and low thermal expansion characteristics. Our piston seats onto an internal O-ring to create a perfect seal, eliminating boost leaks common in OEM and cheap aftermarket BPVs. In order to make sure this could keep up with high power levels, we chose to use a massive 38mm diameter piston/sealing ring for the ability to dump pressure quickly. This is especially important on high boost applications to keep the turbo from sustaining damage and the BPV maintaining leak-free operation. A precisely-tuned steel spring alleviates the need for any tuning or adjusting of the valve, with no engine tuning required to run the unit. Buna-N O-rings were the next logical choice due to their resistance to degrading from fuel and oil exposure. In addition, all of our O-ring grooves utilize a single dovetail design for superior retention. This guarantees the O-ring will not fall out and has the perfect crush for sealing the body together. To top things off, we employ a swivel fitting on the valve to make for easy installation and accommodate best-routing on custom setups. A GrimmSpeed signature branding badge graces the top of each unit so that everyone will know you chose the best valve in the biz.

When designing the 15-21 WRX (FA) unit we paid special attention to size. This was important due to a high number of hoses, wires and hard parts needing to pass through this same compact space. We were able to keep the same large 38mm piston, but slim down the footprint of the valve making working in that area easier than with the factory part. With the GrimmSpeed Bypass Valve installed, a definite crispness and sound change is noticeable through the intake and due to the leak free nature of our valve, the car builds boost much more quickly over the leak-prone OEM version.