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Electronic Boost Control Solenoid 3-Port - Subaru 08-17 STI

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Product Description

The Original Direct-Fit BCS for turbo Subarus.

GrimmSpeed is proud to provide the most complete and easy to use 3-Port Electronic Boost Solenoid for available for all turbo Subarus. Unlike your OEM 2-port solenoid, the GrimmSpeed BCS will allow for extremely high resolution boost control, providing your tuner with the hardware he needs to safely tune your car with rock solid boost levels. Using our solenoid, you are able to spool your turbo quicker and maintain tight control of boost levels throughout your power curve. In addition, our solenoid features a balanced valve to withstand up to 120psi without a slowing response by even a single millisecond. 

Quick Specs

  • Decrease Spool Time - flows 10% more than the competition 
  • Plug and Play into OEM Harness - no splicing wires like other BCS solutions
  • Works Safely with Factory Subaru ECU - custom coil to match ECU voltage
  • Nickel Plated Fittings - not the easily breakable plastic fittings!
  • 15min Installation - extremely simple with our written and video guides


Revolutionizing the Subaru boost solenoid market, we have created model specific install brackets that allow you to install our Boost Control Solenoid with a factory fit and finish. To top it all off, our solenoid also uses a Subaru wiring harness connector so that you can simply unplug your OEM solenoid and plug ours in. No more cutting and crimping OEM wires together!

The solenoid itself is one of a kind. MAC manufactures pneumatic control products for the largest commercial operations in the world, where every minute of downtime can cost tens of thousands of dollars, so we worked closely with their engineers to design this unique valve, incorporating proprietary features, exclusive to GrimmSpeed, that make our solenoid the toughest on the market. Those features include special seals to protect it from moisture and high temp coils to keep response times at 6 milliseconds or less, even in extreme heat. We have worked with many of the top tuners in the country to ensure that our solenoid works safely with the factory Subaru ECU.



Our special solenoid features, combined with our factory-fit brackets, ensure that this complete boost control solution will withstand the harsh heat and vibration of your engine bay. The Subaru harness connectors that we use include weatherproof terminal seals, carefully crimped with DELPHI equipment by our expert assembly staff. Mounting brackets are laser cut and then black zinc plated to ensure corrosion resistance. Each bracket has threaded PEM nuts pressed in for a solid connection with no risk of stripping threads. Each low profile 1/8" NPT nickel plated fitting is installed in the proper orientation using a 120psi thread sealant for a clean, compact, robust installation.


Trust Your Tuner

You don't need to take our word for it, trust your tuner. When it comes to boost control systems, be sure to consult with your tuner to ensure that you're building a setup that they're confident tuning. The good news is that with well over 25,000 units in use on some of the fastest Subarus in the world, with the GrimmSpeed Boost Control Solenoid, you'll be in great company. As with any change to your boost control system, upgrading to a 3-port solenoid does require tuning.


"The GS 3-port BCS provides rapid boost response while maintaining the ability to make acute adjustments via turbo dynamics. While many other boost control solenoids react to adjustments too fast which can make them difficult to control with as much finesse as the stock bleed system. This solenoid can make micro-adjustments at the edge of target boost not only providing better spool, but overall more control." - AWD Tuning

"The GrimmSpeed™ BCS is a compact, well designed unit. Its design as a 3-port solenoid provides better boost control then the stock bleed-type style. Often, this enables a tuner to cut mapped wastegate duty cycles in half. This change in WGDC gives a tuner more granularity when tuning, and can yield much improved boost curves. In addition, the 3-port design often significantly improves spool." - Bullwinkle Tuning


  • 2008 Subaru STI
  • 2009 Subaru STI
  • 2010 Subaru STI
  • 2011 Subaru STI
  • 2012 Subaru STI
  • 2013 Subaru STI
  • 2014 Subaru STI
  • 2015 Subaru STI
  • 2016 Subaru STI

Product Videos

GrimmSpeed Boost Control Solenoid Install (06:29)
GrimmSpeed introduces the most complete and easy to use 3-Port Electronic Boost Solenoid available on the market. Our aftermarket boost controller allows you to raise the OEM boost levels in a quick and efficient manner. If you try to raise the boost on the weak OEM boost solenoid it will start to become unpredictable and unable to maintain proper and safe boost levels. Using our solenoid you are able to spool your turbo quicker and maintain a rock solid boost level. We have made our solenoid to withstand 120psi, way more than any Subaru will see.
  • GrimmSpeed Boo...
    GrimmSpeed introduces the most complete and easy to use 3-Port...
  • GrimmSpeed Boo...
    We conducted a comparison test between our valve and other kno...
  • BCS Intro_v2_v...
    GrimmSpeed's Boost Control Solenoid Highlighted
  • Grimmspeed EBC...
    Installed Grimspeed EBCS. Car runs a lot better and more respo...
  • GrimmSpeed Boo...
    GrimmSpeed introduces the most complete and easy to use 3-Port...
  • 2008-2012 SUBA...
    I just made a quick video on how the GRIMMSPEED EBCS is hooke...
  • Grimmspeed 200...
  • 2006 Subaru ST...
    Dyno vid of my 2006 Subaru STI.Cobb AccessportCobb Catless TBE...
  • 2005 wrx stage...
    2005 wrx 4th gear dyno pullMods:Ebay downpipeSpt/ bosal catbac...

Product Reviews

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Product Reviews

Showing reviews 1-10 of 32 | Next

  1. Great product

    Posted by Mozak

    Great product by GS, was easy to install and was highly recommended by my tuner.

  2. keeps my stage 2 sti's boost under control

    Posted by phibao trinh

    Docked one star due to lack of instructions for STI vacuum hose configuration in the official GS install video.

    Other than that, tuner said boost was controlled perfectly with my Catless GS DP matted to a perrin CBE and intake with a Cobb protune.

    No over boosting for this guy!

  3. Good investment

    Posted by Bruce

    Easy installation works great for tuning the Subaru

  4. 2nd one I have bought and installed.

    Posted by Jon

    ...and like before, perfect.

    I am sold on this EBCS in so many ways. The install is super easy and the boost stays consistent. I would not use any other EBCS, period.

    Thanks again

  5. Great!

    Posted by Lance

    Great response, coming from using the oem boost control this one feels more responsive, boost comes on a lot quicker and my tuner was able to really dial in my car. It feels great now!

  6. EBCS - Awesome!

    Posted by Josh

    Got the EBCS very quickly from GS, install was easy, car made 300 easy with steady and precise boost control!

  7. Absolutely amazing product.

    Posted by Unknown

    Recently purchased this 3 port ebcs to replace my stock one that malfunctioned on my 05 LGT. It absolutely blew my mind away how much it opened up the entire system and advanced throttle response. Highly recommend for anyone needing a replacement or just wants quicker response from their vehicle.

  8. A Must By!

    Posted by Andrew

    Really locked down my boost! Peaked where I wanted it to. Allowed tuner to fine line everything as far as turbo!

  9. Easy installation, greatly reduces turbo lag

    Posted by Jamie

    2004 wrx, stage 1 (Cobb v3) on 93 octane. Installed this EBCS and got a pro-tune. The car is finally pulling as hard as I want it to be. I may go stage 2, but for now I am very happy with the results.

  10. Works for ver5-6 STI as well!!

    Posted by Scott

    Very excited to say that this product was 100% compatible with my version 6 sti engine!! Fit perfectly onto the jdm bracket and plugged directly into the harness. Works flawless, very happy customer!!

Showing reviews 1-10 of 32 | Next