GrimmSpeed's Boost Control Solenoid Is The Best Mod Under $200

There are a few established companies in the Subaru performance industry that have really made an impact on pushing the platform of Subaru engines. One of those companies that comes to mind is GrimmSpeed. Over a decade ago, GrimmSpeed greatly recognized the potential of the EJ, and went on an unrelenting quest to provide enthusiasts with products that add more power while improving the overall driving experience.

To highlight some of their products, GrimmSpeed recognized that the WRX and STI were prone to heat soak, and heat soak is when the intercooler fails to lower the incoming intake charge temps coming from the compressor wheel of the turbocharger, feeding the intake manifold with warmer air. When heat soak happens, you hit the limit on your performance, and not the potential. The WRX and STI both have inherently small top mount intercooler setups, and if you live in an area that experiences extreme heat, or if you’re in 90° temps, then you could experience heat soak. The solution was a top mount intercooler that had a thicker core. This would keep the intake charge temps cool enough to increase the performance, but it also can support up to 400 HP. Today, GrimmSpeed has several intercooler options with newer designs to work with all generations of the WRX and STI:

GrimmSpeed Top Mount Intercooler 2002-2007 WRX / 2004-2021 STI

 

Another great upgrade from GrimmSpeed is their Cold Air Intake Systems. Subaru’s OEM intake designs leave a lot on the table for improvement. The turbo inlet hoses will crack or tear at some point leaving unmetered air to get passed the MAF which will cause a check engine light. And like all turbocharged vehicles, the factory airbox with paper filter makes the turbo struggle to breathe, causing the turbo to work harder. GrimmSpeed’s cold air intake allows the turbo to inhale a larger volume of air which frees up a substantial amount of horsepower, while reducing turbo lag and improving the throttle response. When paired with a tune by a COBB Accessport, you get the maximum power potential from the GrimmSpeed intake while smoothing out the powerband. A great investment that offers a better driving experience as a return.

GrimmSpeed Stealthbox Cold Air Intake 2015-2018 WRX

 

Moving onward onto the path of basic modifications before we move onto the main feature, what goes along greatly along with a larger intercooler, and a cold air intake goes without saying. You need a good cat-back exhaust system. A cat-back is typically the first modification all car guys perform to their pride and joys, because it is the most rewarding mod. You get the increase in power, but more importantly you get the sound. For those of you with a 2011-2021 WRX, GrimmSpeed’s Cat-Back Exhaust System is fabricated art in stainless steel. With the flat-four engine in the Subaru, one of the most distinctive characteristics is that flagship Subaru rumble. It doesn’t sound like any typical four-cylinder engine, and GrimmSpeed knows how to put that element on blast. You get an increase in piping diameter, smooth bends in the piping, and a pair of mufflers to wrangle the noise in. Loud, but not too loud. Just right from idle to the top of boost, this exhaust system will satisfy your eardrums while giving your WRX a more pronounced sound.

GrimmSpeed Cat-Back Exhaust System Non-Resonated 2011-2021 WRX/STI Sedan

 

And for the main course on tonight’s menu, the GrimmSpeed Boost Control Solenoid:

GrimmSpeed Boost Control Solenoid 2006-2007 WRX / 2004-2007 STI

 

 

The OEM boost control solenoid for the turbocharged Subaru models has been a component that badly needed replacing as it blocked performance and potential from the turbocharger. Particularly in the control as it was programmed to do exactly what the ECU told it to do from the factory. The solution? GrimmSpeed added another port and designed it to work lighting fast to improve the boost response in any boost range you have your Subaru programmed to hit. And it hits the strike zone every time. In fact, the GrimmSpeed Boost Control Solenoid works so well, that it has been one of their most highly utilized and purchased items. The factory boost control solenoid will bleed the signal traveling between the turbo and wastegate, causing a slower response that at times, is unpredictable. GrimmSpeed’s 3-port solution interrupts the boost signal traveling from the turbocharger to the wastegate which delivers a precision signal every time so that you are maximizing your turbocharger’s boosting potential.  

Llet’s look at some of the features that makes this unit so desirable, and a needed part in the overall menu of modification:

• Designed to decrease the spool time, with an extra port to maintain optimal control.
• Designed with a proprietary internal modification design prepares the solenoid for extreme conditions below the vehicle.
• Plug and play operation directly into the factory wiring harness with no modification required.
• Works safely with the factory ECU.
• Provides a quicker, and more precise boost control response.
• Makes tuning simpler, and direct for the tuner.
• The solenoid will include nickel-plated fittings.
• Designed with a plug-and-play connector.
• Includes a laser-cut and CNC bent steel bracket that is zinc plated with stainless press-in nuts.
• Includes ¼” vacuum hose w/ zip ties.

 

With the success of their design, GrimmSpeed decided to produce their solenoids for other makes and models outside of Subaru to improve their boosting performance as well.

The GrimmSpeed Boost Control Solenoid works excellent with MazdaSpeed’s platform, as the MazdaSpeed 3 and 6 are known to make substantial horsepower gains from something as simple as a cold air intake. Just make sure you have the supporting mods such as an Accessport, and the fuel pump to utilize the power.

GrimmSpeed Boost Control Solenoid 2007-2013 MazdaSpeed 3

 

 

GrimmSpeed Boost Control Solenoid 2008-2015 Evo X

The Mitsubishi Evolution X from 2008-2015 with it’s 4B11 platform has proven to be a street and track weapon, winning several grassroots fastest time-of-the-days, SCCA events, as well as several time attack and Hillclimb wins. The 4B11 has a fast-responding engine, and with the help of GrimmSpeed’s BCS, the turbo hits it’s intended boost control settings every time.

 

 

 

 

 

Finally returning back to Subaru, here is another great example for the everyday WRX with the FA20DIT known as the 2015-2021 WRX:

GrimmSpeed Boost Control Solenoid 2015-2021 WRX / 2014-2018 Forester

 

 

 

For the affordable price, ease of installation in terms of being a plug-and-play installation, the GrimmSpeed Boost Control Solenoid is a must-have on your build list. Modifications such as an intake and an exhaust will naturally raise boost levels because you free up restrictions in the OEM design, which allows the turbo to spool more efficiently. But don’t overdo it, keep it under control with a proper solenoid.