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An Elegantly-Engineered Solution.

If you've been in the Subaru game for long, you're probably well aware that a 3-port Electronic Boost Control Solenoid (EBCS) is considered by most to be a 'must have' improvement before having your car tuned. GrimmSpeed has become the trusted brand in the EBCS market, with tens of thousands of solenoids in operation today across the globe.

The 2015-21 WRX offers a unique change of pace, as the factory 2-port solenoid is mounted directly to the plastic turbo inlet and interfaces with an o-ringed feature, rather than a vacuum hose. With expertise in designing machined parts and a tried and true boost control solenoid, we were excited to dig in and create a solution with an already proven pedigree of high performance and quality.

Quick Specs

  • Custom Machined Adapter - Makes use of the factory inlet port, sealed w/ VITON O-Ring
  • Black Anodized Finish - Protects the assembly from corrosion in an extremely demanding environment
  • 1/4in Barbed Fittings – Zinc plated, sizing matches the factory turbo and included hoses
  • 3-Port Solenoid - Proprietary internal modifications prepare the solenoid for extreme automotive conditions
  • Custom Wiring Connector - Plugs directly into the OEM wiring harness with no modification or splicing required
  • Compact Design – Mounts directly in factory location w/ included adapter and zinc-plated steel bracket

The 3-Port Advantage

boost-solenoid-2015wrx-8-framed-1600.jpg   bcs-subaru-fa20-5-original.jpg

The advantages of a 3-port boost control system vs. the factory 2-port are readily apparent during the tuning process. The 3-port systems work by interrupting the boost signal traveling from the turbo to the wastegate. That boost is redirected back into the turbo inlet and re-ingested by the turbo using our machined adapter. This is important, as the factory Mass Airflow Sensor has already measured that air and is expecting that your motor will use it during combustion, rather than venting it to the atmosphere. The factory configuration simply 'bleeds' the signal from between the turbo and wastegate, which creates a system that is a bit less complex, but reacts more slowly and with less precision. The chart above shows two boost plots. The 'before' is our 2015 WRX, dyno tuned by a third party protuner. The 'after' is the exact same tune, but after the installation of the GrimmSpeed 3-Port EBCS. As you can see, the addition of the GrimmSpeed EBCS shows much tighter boost control and consistency. This is safer for your car and easier for your tuner to work with.



We began by recreating the factory turbo inlet and solenoid in CAD to ensure a perfectly fitting system. From there, we designed a beautifully-fitting machined adapter that would recreate the o-ring sealing feature that the factory solenoid uses. This bracket features 1/8" NPT threads so that both [included] barbed fittings or AN fittings can be used interchangeably, for use with the GrimmSpeed EBCS, Manual Boost Controller, or other boost control solutions.

A small mounting bracket secures the solenoid to the machined adapter to create a compact system, while still allowing those interested in running other boost control solutions the flexibility to do so. Mounting our solenoid directly in place of the stock solenoid allows for vacuum hoses of similar length and a shorter wiring harness. Lastly, we identified the exact electrical connector used on the stock solenoid so that the GrimmSpeed solution would be a true plug and play one.

Why GrimmSpeed?

The GrimmSpeed Boost Control Solenoid has been proven time and time again. With tens of thousands on vehicles across the world, tuners trust it and our customers love it. What you see here is the same great solenoid with millions of miles of real world testing and an innovative mounting solution, designed specifically for your vehicle. The machined adapter also features standard NPT threads, should you choose to upgrade to AN lines and fittings, or even a different boost control solution (manual, standalone, hybrid, etc). Finally, the GrimmSpeed EBCS system will arrive fully assembled and ready for installation.

Tuning Notes

Since this upgraded solenoid affects the way that your vehicle controls boost (that's the point!), it is always recommended that you consult with a tuner immediately following installation. It is not recommended that you drive the car in a way that builds boost without proper tuning. If you have any questions, don't hesitate to get in touch with us directly!


22 Reviews

Sam Dodson 26th Jul 2021

So much better than stock

I had so much luck with getting this, my tuner was able to safely tune my car for higher boost, and it actually made it so I could hit those boost numbers as soon as I installed it. 100% worth the money.

Michael T 23rd Jul 2021


Super easy to install and it's a Grimmspeed product so it speaks for itself, craftmanship is top notch. These guys are miles ahead of amazing customer service. Not only did they have it shipped out an hour after ordering it, they upgraded it to priority shipping just because. I've had a previous exprience where they shipped me out a backordered Jpipe in record time and I swear if Grimmspeed made every part thinkable for my Subaru, I'd buy from them forever.

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