If you’ve been in the Subaru game for long, you’re probably well aware that a 3-port Boost Control Solenoid (BCS) is considered my most to be a ‘must have’ improvement before having your car tuned. GrimmSpeed has become the trusted brand in the BCS market, with tens of thousands of solenoids in operation today across the globe.
The 2015 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.
Enter the GrimmSpeed 2015 Subaru WRX 3-Port Boost Control Solenoid, the first and only of it’s kind.
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 barbed fittings (included) and AN fittings can be used interchangeably, for use with the GrimmSpeed BCS, 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 the solenoid directly in place of the stock solenoid allows for vacuum hoses of similar length and a shorter wiring harness. We contemplated the option to make a fully integrated solenoid, but decided that creating an adapter and mounting solution allowed people to use a solenoid that’s already been heavily tested and that tuners are familiar with. One possible change between now and production is to integrate the BCS mounting feature into the adapter. Cost and complexity will determine if that’s feasible shortly.
Lastly, we worked to identify the exact electrical connector used on the stock solenoid so that the GrimmSpeed solution would be a true plug and play (differs slightly from the connector pictured). After that, we went ahead and built prototype and pre-production units.
As a brief overview of the advantages of a 3-port boost control system vs. the factory 2-port system, the 3-port systems works by interrupting the boost signal traveling from the turbo to the wastegate. That boost is redirected back into the turbo inlet (post-MAF sensor) and re-ingested by the turbo. 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.
We’re currently finalizing the detailed design and moving into production. As soon as we have an estimated release date (expected 2-3wks), we’ll begin accepting pre-orders at a discounted group buy price. We’ll start a different thread for that when the times comes, so for now, let’s keep this discussion technical.
The next step is to get a small initial batch of solenoids into the hands of your favorite local tuners. If you’re a tuner yourself or you’d like to nominate a tuner for receipt of a prototype unit, please comment below and we’ll add you to the list. From this list, we’ll select testers based on experience and geographic location.