GrimmSpeed 3-Port EBCS for 2015-2021 Subaru WRX (FA20) – Precision Boost Control Upgrade
An Elegantly Engineered Solution
A 3-port Electronic Boost Control Solenoid (EBCS) is widely considered a must-have upgrade before tuning any turbo Subaru, and GrimmSpeed has become one of the most trusted names in boost control with tens of thousands of units in use worldwide.
The 2015-2021 Subaru WRX features a unique factory design where the OEM 2-port solenoid mounts directly to the plastic turbo inlet using an O-ring seal instead of traditional vacuum hose routing. GrimmSpeed engineered a purpose-built solution that retains the factory mounting style while delivering the superior boost control and responsiveness of a true 3-port system.
Key Features & Quick Specs
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Custom Machined Adapter utilizes the factory inlet port and seals with a Viton O-ring
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Black anodized finish for maximum corrosion resistance
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1/4” zinc-plated barbed fittings matched to factory hose sizing
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GrimmSpeed 3-Port Solenoid with proprietary internal modifications for extreme under-hood conditions
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True plug-and-play wiring connector (no splicing or harness modification required)
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Compact direct-mount design installs in the factory location using the included steel bracket
The 3-Port Advantage
Compared to the factory 2-port solenoid, a 3-port system provides dramatically improved boost control resolution by interrupting the boost signal between the turbo and wastegate. Instead of bleeding off pressure like the OEM design, the GrimmSpeed setup redirects air back into the turbo inlet—keeping the air properly accounted for by the MAF system.
The result is tighter, more consistent boost control, improved safety, and a setup that tuners prefer because it allows for more accurate tuning and smoother boost curves.
Engineered for Factory Fit & Finish
GrimmSpeed developed this kit by recreating the factory turbo inlet system in CAD, allowing them to design a machined adapter that perfectly replicates the OEM sealing surface. The adapter includes standard NPT threads, giving flexibility for barbed or AN fittings and compatibility with alternative boost control setups.
The solenoid mounts directly in the stock location, keeping hose lengths short and installation clean, while the custom connector ensures a seamless OEM-style plug-in.
Tuning Note
This upgrade requires tuning. It is strongly recommended not to drive aggressively or build boost after installation until the car has been properly tuned.
Fitment
2015-2021 Subaru WRX (factory composite turbo inlet or GrimmSpeed aluminum turbo inlet)