The Intercooler Upgrade Guide for the Subaru WRX (FA20DIT). The 2015-2021 VA Subaru WRX with the flat-four FA20DIT engine is a terrific car that reacts well to performance upgrades. We previously discussed the finest Downpipe/J-Pipe for the WRX (VA), and now we’re looking at intercoolers. Intercoolers are excellent additions for individuals trying to reduce charge air temperatures, which is critical on a turbocharged engine like the FA20. In this post, we’ll look at the advantages of upgrading your Subaru WRX intercooler, as well as the various options available. Continue reading to learn about the best intercooler for the 2015-2021 Subaru WRX.
The Fundamentals of Subaru WRX Intercoolers
First, let’s define what an intercooler is. The goal of improving the WRX intercooler is to lower the temperature of the air that enters the engine. Because turbochargers are driven by engine exhaust gases, they are subjected to severe temperatures. Furthermore, because air heats up as it compresses, the boost (also known as charge air) that comes out of a turbocharger can become extremely hot.
Intercoolers are situated between the turbocharger and the engine in the intake system. They cool the compressed post-turbo air, eliminating heat and adding oxygen before it enters the engine. Because colder air contains more oxygen than warmer air, it generates higher horsepower and torque.
When compared to the factory unit, upgrading the WRX intercooler improves cooling efficiency and recovery time. The FA20’s default intercooler is adequate for factory power levels, but it quickly gets outmatched at anything higher. Furthermore, the stock unit does not hold up well to repeated pulls and heats up quickly in the summer. A larger intercooler solves both of these problems by reducing charge air even after many runs.
The Subaru WRX with the FA20, like many other vehicles, employs an air-to-air intercooler. It is top-mounted over the engine, which is where the characteristic hood-scoop of the automobile comes into play. Through the hood-scoop, ambient air enters the engine area and washes over the intercooler. This cools the intercooler and keeps it from overheating, as well as allowing it to cool the charge air.
Design and Location of the Subaru WRX Intercooler
There are two types of intercooler improvements for the Subaru WRX: front-mount intercoolers (FMIC) and top-mount intercoolers (TMIC). TMICs are standard equipment on the WRX. They bolt up to the OEM charge pipe and throttle body and fit straight into the WRX’s stock placement. FMICs, on the other hand, position the intercooler behind the car’s front bumper, directly in front of the radiator. They also replace the OEM charge pipe and are not always compatible with the OEM intake.
Adequately sized FMICs will nearly always exceed TMICs in terms of performance.
Top Mount Intercoolers for the WRX
The first category is top-mounted intercoolers. Because they maintain all of the OEM intake components, TMICs are much easier to install on the WRX. They also use the OEM hood scoop to keep the engine bay cool.
Top-mount intercoolers will also be less expensive than front-mount intercoolers for the WRX. TMIC cores are often smaller than FMIC cores, owing to space constraints inside the engine bay. Top-mounts use significantly less pipe than front-mounts for the FA20DIT due to their placement. This minimizes the amount of space the charge air must travel before reaching the engine, reducing lag.
Front Mount Intercoolers for the Subaru WRX
Let us now discuss front-mounted intercoolers. FMICs are substantially more difficult to install than top-mounts and usually necessitate some additional bumper modification. Front-mounts frequently do not connect neatly to the factory intake system, necessitating the purchase and installation of a new intake. Furthermore, to suit the WRX, the inside of the bumper is normally chopped and shortened to accommodate the core.
FMICs also have far more piping than TMICs, which increases lag slightly because the charge air has a longer distance to go. To compensate, FMICs often have larger cores than top-mounts and offer higher efficiency.
The ability to combat heat soak is likely to be the most significant benefit of switching to a front-mount intercooler. FMICs are significantly cooler than TMICs since they are located in front of the engine rather than on top of it. This helps to avoid heat absorption, resulting in better cooling and lower intake temperatures for the FA20.
TMIC vs FMIC WRX: Which is better for me?
When picking between a TMIC and an FMIC, there are several key factors to consider. The most significant difference will be price, as FMICs are significantly more expensive than TMICs on the WRX. Front-mounts typically necessitate the purchase of a new intake as well as bumper modification, as well as the replacement of the OEM crash protection bar, which can be dangerous.
Front-mount intercoolers outperform top-mount intercoolers when it comes to heat soak. TMICs are located on top of the engine, where they constantly accumulate heat and can become heat soaked more easily. Because FMICs are located in front of the engine and radiator, they do not absorb nearly the same amount of residual heat. The bumper opening is also larger than the hood-scoop opening, allowing FMICs better access to cooler ambient air.
On the WRX, most TMICs are highly effective, making the distinction between them and FMICs less evident. For the FA20, the TMIC and FMIC are usually equal for the first few pulls and runs. A FMIC shines when used for extended periods of time, such as on the track. A TMIC intercooler will sufficient on most daily driven and weekend warrior WRXs. Regular track days (Auto-X, Rally, Rally-X, Time Attack, etc.) might benefit from an FMIC during the dog days of summer.
Advantages of FA20 WRX Intercooler Upgrade
The following are some of the advantages of Subaru WRX intercooler upgrades:
- 10 to 45 horsepower
- +10-30 pound-feet of torque
- More consistent performance
- Charge air temperatures have been reduced.
- Heat soak at a lower temperature
- Preventing detonation and pre-ignition
The most noticeable benefits of a WRX intercooler upgrade will be increased horsepower and torque, as well as lower intake temperatures. Without any tweaking, peak power improvements will be in the range of 10-25 horsepower and torque. Tuning can result in improvements of up to 45 horsepower and 30 pound-feet of torque.
Getting an analogous tune with your intercooler, on the other hand, is where you will really start to see benefits. Tuners can run higher amounts of boost and ignition timing without experiencing detonation due to the enhanced cooling provided by a larger intercooler. This means that not only will peak power increase, but so will the entire power range, raising average horsepower as well.
Aside from better power figures, you’ll notice lower charge air temps, which is what’s causing the improved power. When heat soaking is used, the temperature difference between the charge air and the ambient air can reach 50-60°. A larger intercooler will reduce this significantly, usually to within 10-15° of ambient temperature, if not to ambient temperature itself.
This signifies that your engine is receiving the coldest air possible (you cannot cool below ambient using only air). As previously stated, cooler air contains more oxygen and causes less detonation and pre-ignition. The hotter your climate, the more useful an intercooler improvement will be.
Intercooler Upgrades for the FA20 WRX
Okay, now that we’ve covered the basics of intercoolers and their benefits for the WRX, let’s take a look at our picks for the finest FA20 WRX intercoolers on the market. Top-mount intercoolers are listed first, followed by front-mount intercoolers.
This is not an exhaustive list of VA WRX intercoolers, but these are the best options in terms of craftsmanship, pricing, and performance. These intercoolers will fit all VA WRX models from 2015 to 2021.
WRX Cobb Tuning Intercooler
1) WRX GrimmSpeed TMIC with Splitter
Price: $889.00
Top-Mount Style
The GrimmSpeed Top-mount intercooler for the FA20 WRX is our top pick for TMICs. Anyone who is knowledgeable with Subaru knows that GrimmSpeed is unquestionably one of the best American-made brands, and their TMIC is a beast. It has a 13.1″ x 10″ x 3.75″ Cross Flow Core and a two-piece splitter that is entirely integrated. It comprises cast aluminum end tanks and a pre-drilled bung for easy insertion into a water/methanol system.
The WRX GrimmSpeed TMIC may add 10-25 horsepower to the FA20 without a tune and 15-35 horsepower with one. Its fit and finish are excellent, and the integrated splitter replaces the factory device with a considerably more efficient unit. When compared to the original unit, intake temperatures are lowered by up to 40°.
GrimmSpeed items are entirely designed and manufactured in Minnesota, and they are all TIG welded. Their FA20 WRX TMIC is one of the best, if not the greatest, TMICs on the market at an affordable price. I installed and used this intercooler on my WRX for several years and it worked flawlessly.
2) Garrett Motion Top-Mount Intercooler for Subaru WRX
Price: $700.00
Top-Mount Style
The Garrett Motion FA20 WRX Top-Mount Intercooler is our second-ranked top-mount intercooler. Garrett is a leading aftermarket and OEM turbo producer, and their intercooler technology is second to none.
The Garret TMIC for the FA20 WRX has a 13″ x 10.2″ x 4″ core that can produce up to 530 horsepower. It is 70% bigger than standard and can offer up to 16 horsepower and torque increases. Under WOT, users should notice a drop in intake temperatures of up to 30°. It’s also excellent for recovering between WOT runs and multi-gear pulls.
The Garret TMIC does not have the same performance as the GrimmSpeed, but it is significantly less expensive. It’s an excellent low-cost alternative for people wishing to upgrade without breaking the bank. In the classifieds, used ones are frequently available for $400-500.
3) Front-Mount WRX Cobb Tuning Intercooler
Price: $2,025.00
Front-Mount Design
The Cobb Tuning FA20 WRX Front-Mount Intercooler Kit is our first front-mount intercooler on the list. Cobb is an internationally renowned performance company and the most well-known manufacturer of Subaru performance parts. Their Accessport ECU tuner is responsible for much of their success, but their hardware is also excellent.
The Cobb WRX FMIC has a massive 24″ x 11″ x 4″ core with 2.5″ pipework. It is capable of enormous horsepower boosts while remaining frugal on mid-range designs. It is only compatible with the Cobb Big SF Intake, therefore you must purchase them together. Unlike many other WRX FMICs, the Cobb unit requires just minor modifications to the WRX’s undertray.
One of the most appealing features of the Cobb front-mount is that it is completely CARB compliant. Users can expect up to 45 horsepower improvements after a tune, as well as a reduction in charge air temperatures to near ambient.
4) GrimmSpeed FMIC Subaru WRX
Price: $1,559.00 – $1,878.00
Front-Mount Design
Along with their TMIC, the GrimmSpeed FA20 WRX Front-Mount Intercooler Kit is on the list. It has a large 27″ x 11″ x 4′′ Cross Flow Core that can accommodate designs with low, medium, and high horsepower. The GrimmSpeed FMIC boasts the largest core of any of the intercooler kits on our list.
The GrimmSpeed front-mount intercooler will suit either the standard or GrimmSpeed intake on the FA20 WRX. Users can expect up to 35-40 horsepower with an accompanying tune, as well as a 40° drop in intake temps. GrimmSpeed is well-known for their exceptional fitment and craftsmanship, and their FMICs are top-of-the-line.
5) Front-Mount Intercooler WRX FA20 PRL
Price: $1,295.00
Front-Mount Design
The PRL FA20 WRX Front-Mount Intercooler Kit is the next item on our list. PRL was one of the first firms to make FMICs for the VA WRX, and their devices have received excellent reviews and have been utilized on numerous high-performance builds.
The PRL FMIC is 22″ x 12″ x 3.5″ in size and can produce up to 600 horsepower. They claim that their FMIC outperforms the stock TMIC by a wide margin. They promise up to 40 horsepower without a tune, as well as dramatically better middle improvements. And claim up to 60-75 horsepower above standard with a tune and simple supporting mods – albeit that’s a touch more doubtful.
The PRL is the best FMIC for the money on the list. It is the most affordable option while still providing outstanding gains, and it is recommended by several professional tuners. Though they had been retired for a few years, PRL stated in early 2023 that they will be reintroduced.
6) FMIC Upgrade for Subaru WRX ETS
Price: $1,554.00 – $2,104.00
Front-Mount Design
The ETS FA20 WRX Front-Mount Intercooler Kit is the final inclusion on our list, and it is one of the most well-known. ETS, like PRL, created one of the first FMIC kits, which were utilized on several legendary and massive horsepower builds. The ETS FMIC was used in the first 9 second Subaru WRX with the FA20.
The ETS core measures 26″ x 11.37″ and comes in three thicknesses: 3″, 3.5″, and 4″. An alternative titanium brushed pipe kit is also available for improved cooling on the cold side. With the ETS FMIC, users can likely expect 30-35 horsepower improvements from the FA20, as well as intake temperature savings of up to 40°.
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Summary of Subaru WRX FA20 Intercooler Upgrade
For the FA20 Subaru WRX, an improved intercooler is a wonderful performance and reliability mod. Intercoolers not only increase horsepower and torque, but they also reduce heat soak and allow for more consistent and prolonged performance. Reduced heat soak reduces the likelihood of serious engine problems such as misfiring, pre-ignition, or knock, which extends engine longevity significantly.
Anyone making more power than stock or living in a hot climate should strongly consider upgrading their VA WRX intercooler. The benefits are not as visible in the winter, but they are highly noticeable in the summer and can help save your engine. Using a tune in conjunction with your intercooler provides the most bang for your buck and the greatest gains.
The GrimmSpeed and Garrett top-mount intercoolers on our list are both excellent choices. The GrimmSpeed is slightly more expensive, but it provides superior performance and cooling. The PRL is the most affordable of our front-mount intercoolers while still providing excellent performance. The Cobb and GrimmSpeed FMICs have comparable performance, but the GrimmSpeed is less expensive and contains the largest FMIC core of all. The ETS is the most tried and tested FMIC for the FA20 WRX, and it has been used in some famous builds.
They are all designed to fit all VA WRX years (2015-2021), therefore the true choice is between a top-mount and a front-mount. Top-mounts are less expensive and quicker to install, but they provide inferior performance and resistance to heat soak on the FA20DIT.
