GrimmSpeed Bypass Valve - 02-07 WRX, 04-21 STI

( 3 Reviews )

Current stock: 0

It appears that you’re not the only one with excellent taste in premium automotive components! Unfortunately, both the red and black versions are temporarily out of stock, however should become available soon. You can still place your order and be put in a queue; the item will be shipped ASAP. Please contact our customer service via email or phone (612-379-0000) with questions, or check for availability with our retailers, thanks!

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

The long-awaited GrimmSpeed Bypass Valves are here! 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. Best of all, we’re offering these BPVs in all of the major EJ and FA engine fitments including the 08-14 WRX/05-09 LGT, 04-21 STI and 15-21 WRX.

Quick Specs

  • 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


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 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 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 degradation 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.

 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.


  • 04-21 Subaru STI

  • 02-07 Subaru WRX

  • 06-08 Subaru Forester XT

  • 04-05 Subaru Forester XT (with STI-Style TMIC)

  • 04-06 Subaru Baja XT (with STI-Style TMIC)

3 Reviews

Adrian Tee 7th Jan 2023


Easy installation with addons grimmspeed bypass valve gasket, a bpv/bov sound been wanting so looong

KP 29th Nov 2022

Recerculating Blowoff Valve

If you have wondered what to buy next for your wip, buy this! I have the typical bolt on stuff but this valve has made the biggest impact and at high RPMs it makes a cool wowowo sound. It is apparent that my old stock valve was allowing A LOT of psi blow by. Install was too easy. It comes with an o-ring so if you have a front mount cooler it will attach to the inlet pipe adapter. Grimmspeed thanks.

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