GrimmSpeed Bypass Valve - 15+ WRX

( 3 Reviews )

Current stock: 0

It appears that you’re not the only one with excellent taste in premium automotive components! Unfortunately, this product is 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 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.


  • 15-21 Subaru WRX

  • 14-18 Subaru Forester XT

3 Reviews

Andrew Hope 20th Jun 2022

It's the wastegate you need, not want

I bought this and the inlet together around the same time. I got them not too long after and upgraded immediately. My entire emphasis with my build is on efficiency and not being too invasive with the already great platform the fa20dit has. Even so the pieces that need the most fixing on these cars is the inlet and the wastegate. They leak like crazy! Sometimes I would feel like the wastegate was just leaking, and leaking, and wasting not only power, but gas just trying to get it to nominal boost. Not anymore. There is little to NO leaks between these two, and the boost pressure is consistent - making shifting a lot quicker (and frankly more fun). If you were to ask me the three best upgrades for any wrx I would hands down say GS wastegate, turbo inlet, and exhaust (with or without a tune!). Do yourself a favor: pick up the inlet and the wastegate from Grimmspeed and get ready for an exemplary driving experience.

Eliezer 25th Apr 2022

2017 WRS Bypass valve

Best one thank you

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