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Grimmspeed Bypass Valve Red 2004-2021 STI / 2002-2007 WRX

SKU 126024.2
Sold out
Original price $229.00 - Original price $229.00
Original price
$229.00 - $229.00
Current price $229.00

Here, you are looking at the Grimmspeed Bypass Valve for your STI, WRX, Baja, or FXT.


  • 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)

Grimmspeed 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 in either a black or red finish to give them a brilliant appearance, provide corrosion resistance and match other GrimmSpeed offerings. Compared to the stock cast unit on the EJ STI platforms, GrimmSpeed Bypass Valves not only stand out, but are guaranteed to stand the test of time.

For the internal components of the valve, Grimmspeed chose to utilize a machined brass piston for its anti-corrosion and low thermal expansion characteristics. The 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, GS 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.

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. Both the 08-14 WRX/05-09 LGT and 04-21 STI (EJ) fitments utilize the same valve but with different footprints, for use across a broad range of vehicles including Legacies, Foresters and Bajas with the proper intercooler setup. The STI unit reuses the recirculating elbow from the factory BPV, ensuring precise alignment and a perfect fit. All this makes for a total plug-and-play package.


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

    Customer Reviews

    Based on 3 reviews
    Kimberlyn Brockert
    Sounds and looks great

    Waited a long time for this BPV and it was worth it. The only thing I’d recommend is getting a different elbow before hand. I paired mine with a black elbow from IAG and it looks great together.


    Thank you for your 5 Star Review of the Grimmspeed Bypass Valve! I am thrilled to hear that you're happy with your purchase and that the valve sounds and looks great on your STI/WRX. Your recommendation to get a different elbow beforehand as the OEM one can get worn out! This BPV is a perfect replacement from OEM and offers and upgraded aluminum housing and brass internals! It out performs OEM without a doubt! I hope you continue to enjoy your upgrade and thank you for choosing Subimods!


    Brandon Jones
    Best sounding bpv

    Sooo this was a long long awaited wait for this since it was always pushed back due to supply issues but I will say this is the best bpv hands down. I did have a go fast bits but wasn't able to get a good tune with it since it was supposedly leaking. Has the flutter and I'm very impressed with it.


    We appreciate your 5 Star Review! The Grimmspeed Bypass valve is a solid BPV for your WRX/STI! When I say solid the body is CNC machined out of billet 6061 aluminum alloy housing a massive 38mm machined brass piston. Brass was chosen due to the low thermal expansion ensuring your BPV does what it needs to do under the most extreme conditions! The added bonus of it's sound makes this a go to BPV solution!


    Patrick Lydon

    Well built and put together


    Thank you for the 5 Star Review of the Grimmspeed Bypass Valve Red 2004-2021!