Subaru WRX FA20 Intercooler Upgrades - WRX FMIC Mods
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Subaru WRX Intercooler Upgrade Guide (FA20)

Chandler Stark

Meet Chandler

Chandler is an automotive expert with over a decade of experience working on and modifying cars. A couple of his favorites were his heavily modded 2016 Subaru WRX and his current 2020 VW Golf GTI. He’s also a big fan of American Muscle and automotive history. Chandler’s passion and knowledge of the automotive industry help him deliver high-quality, insightful content to TuningPro readers.

Since its debut stateside in 2002, the Subaru WRX has been one of the best tuner cars on the American market. In 2015, Subaru introduced the 2 liter FA20DIT engine, which produced 268 horsepower and 258 lb-ft of torque. While that is already good enough to give the WRX some solid performance, many people have noted the weakness of the OEM intercooler. If you live in an exceptionally hot climate or like to drive your WRX hard, you’ve probably noticed it has some issues keeping up with cooling. That’s why today we’re looking at the top WRX intercoolers to improve performance. Read on to find out which WRX intercooler is the best, and whether a top-mount or front-mount intercooler is right for you. 

Make sure to check out our other WRX content, including: our WRX FAQ, Racing Seat Upgrade Guide, FA24 Engine Guide, FA20DIT WRX Turbo Upgrade Guide, WRX Downpipe Guide, WRX Exhaust Guide, WRX Coilovers Guide, 6 Best WRX Mods, and FA20 WRX vs EJ257 STi comparison guide.

VA Subaru WRX Intercooler Basics

First, let’s talk about what an intercooler does. Intercoolers are located in the intake system between the turbocharger and the engine. They cool the post-turbo air after it has become compressed, removing heat and adding oxygen before it enters the engine. Colder air has more oxygen than warmer air, so it produces more horsepower and torque. 

Turbochargers are powered by exhaust gasses from the engine, so they take on extreme amounts of heat. In addition, as air compresses it also heats up. So the boost (also known as charge air) that comes out of a turbocharger can get exceedingly hot. 

Upgrading your intercooler on the WRX gives you improved cooling efficiency and recovery time compared with the stock unit. The stock intercooler on the FA20 is adequate for factory power levels, but it quickly becomes over-matched at anything above. In addition, the stock unit does not stand up well to repeated pulls and becomes heat soaked rapidly in the summer. A larger intercooler rectifies both of these issues, keeping charge air temperature down even after multiple runs. 

Like many other vehicles, the Subaru WRX utilizes an air-to-air intercooler. It is mounted on top of the engine, which is where the car’s iconic hood-scoop comes into play. Ambient air enters the engine bay through the hood-scoop and washes over the intercooler. This cools down the intercooler and helps prevent it from heat soaking, and allows it to cool the charge air. 

Subaru WRX Intercooler Design and Location

From the factory, Subaru utilizes what is known as a top-mount intercooler for the WRX. Top-mounts sit directly on top of the engine, which is where they get their name. However, many people will relocate their intercoolers to the front of their car between the bumper and the radiator. These are known as front-mount intercoolers, and they provide superior cooling vs top-mount intercoolers. 

Some manufacturers make air-to-water intercoolers, but Subaru has never used those in the production WRX, and there are very few aftermarket WRX air-to-water intercooler kits. 

WRX Front Mount Intercoolers vs Top Mount Intercoolers

GrimmSpeed Top-mounted WRX Intercooler

For most builds, a top-mounted intercooler will be more than adequate on the WRX. As you will see in our recommendations, there are many TMICs rated for well over 500 horsepower, so it is not a power restriction. The one knock on top-mount intercoolers is that since they sit in the engine bay directly above the engine, they can be susceptible to heat soaking.

Heat soaking is when an intercooler becomes too hot and is unable to adequately cool the charge air passing through it. This typically occurs in very hot climates, during repeated runs, and during track use. As the intercooler takes on more and more hot air from the engine bay and turbocharger, it needs to be able to stay cool itself to stay functional. 

This is where the Subaru hood scoop comes in. The hood scoop allows fresh ambient air to wash over the intercooler. This is very effective in keeping down charge air temperatures, and it’s what allows the WRX to so effectively utilize TMICs.

However, even with the hood scoop, top-mounted intercoolers do not hold a candle to WRX front-mount intercoolers. On front-mounts, the intercooler is placed between the bumper and the radiator. This allows for the best access to fresh ambient air, and produces superior cooling vs top-mounts.

The downsides to FMICs are the increased cost and removal of crash-bumper bar (for some models). Compared with a top-mount, a WRX front-mount intercooler will be about twice as expensive. In addition, some models require the removal of the OEM crash bar in the bumper, which can be a safety issue in the event of a crash. 

Which WRX Intercooler is right for me?

For the vast majority of builds under 500 wheel-horsepower, a WRX top-mount intercooler will likely be the best option. They are about half the price of a front-mount, but they still provide more than adequate cooling at 500 horsepower. It’s almost frightening how effective a top-mount is with the WRX hood scoop, and you can see cooling down to ambient temperatures — which is the best possible with an air-to-air intercooler. 

If you plan on going over 500 wheel-horsepower, then a front-mount might be the better option. In addition to being located in a better location, due to the size constraints of the engine bay, WRX front-mounts are able to be much larger than WRX top-mounts. This means they can provide superior cooling on high-horsepower builds.

Another thing that helps FMICs on the WRX is the location of the turbocharger. While many people will argue that FMICs increase turbocharger lag, it’s actually the opposite on the FA20. Due to the low-mount location of the turbo, it sits just inches from front-mount intercoolers. On the FA20 WRX, front-mounts actually require less piping than top-mounts, and will have less lag — though it’s almost impossible to notice due to the twin-scroll turbo’s quick spool. 

Subaru WRX Intercooler Upgrade Benefits

Benefits of Subaru WRX intercooler upgrades for the FA20 include:

  • +10-45 horsepower
  • +10-30 lb-ft of torque
  • Sustained performance during repeated runs
  • Reduced charge air temperatures
  • Reduced heat soak
  • Detonation and Pre-ignition prevention

The biggest benefits you will see from a WRX intercooler upgrade are going to be increases in horsepower and torque, as well as reduced intake temperatures. Peak power increases will be somewhere around 10-25 horsepower and torque without any tuning. With tuning, you can see as much as 45 horsepower and 30 lb-ft of torque gains.

However, getting an equivalent tune with your intercooler is where you will really start to see benefits. Due to the increased cooling of a larger intercooler, tuners can run higher levels of boost and ignition timing without seeing detonation. This means that not only will peak power rise, but the entire power band will see gains, increasing average horsepower, too. 

Apart from higher power numbers, you’ll also see lower charge air temperatures – which is what is responsible for the increased power. With heat soaking, the delta between charge air temperatures and ambient air temperatures can sometimes be as high as 50-60°. A larger intercooler will considerably reduce this, usually to within 10-15° of ambient – if not to ambient temperature itself. 

This means that your engine is getting the coldest possible air it can (you cannot cool below ambient with just air). As we mentioned, colder air means more oxygen and less detonation and pre-ignition. The hotter your climate the more an intercooler upgrade will come in handy. 

Best FA20 Subaru WRX Intercooler Upgrades

The best FA20 Subaru WRX intercooler upgrades are:

  • GrimmSpeed Top-Mount Intercooler
  • Garret Motion Top-Mount Intercooler
  • Cobb Tuning Front-Mount Intercooler
  • GrimmSpeed Front-Mount Intercooler
  • PRL Front-Mount Intercooler

1) Subaru WRX GrimmSpeed TMIC w/ Splitter

Price: $889.00

Design: Top-Mount

The top choice on our list is the GrimmSpeed Top-mount intercooler for the FA20 WRX. Anybody who is familiar with Subaru knows that GrimmSpeed is hands down one of the top American made brands, and their TMIC is an absolute beast. It features a 13.1” x 10” x 3.75” Cross Flow Core with a fully integrated two-piece splitter. It has cast aluminum end tanks and includes a pre-drilled bung for easy water/methanol system integration.

The WRX GrimmSpeed TMIC can give FA20 10–25 horsepower without a tune, and 15–35 horsepower with a tune. Its fitment and craftsmanship are excellent, and the integrated splitter replaces the stock unit with one that’s much more efficient. Intake temperatures are reduced by as much as 40° when compared with the stock unit.

GrimmSpeed products are all 100% made and manufactured in Minnesota and utilize TIG welded construction. Their FA20 WRX TMIC is one of the best, if not the best TMIC on the market, and is at a great price-point. I personally installed and used this intercooler on my WRX for several years and it performed outstanding. Even pushing more than 330 wheel-horsepower with ethanol, the GrimmSpeed still cooled charge air to ambient temperatures.

2) Subaru WRX Garrett Motion Top-Mount Intercooler

Price: $700.00

Design: Top-Mount

Our second ranked top-mount intercooler is the Garrett Motion FA20 WRX Top-Mount Intercooler. Garrett is one of the premier aftermarket and OEM turbo manufacturers, and their intercooler technology is also top-notch.

The Garret TMIC for the FA20 WRX features a 13″ x 10.2” x 4” core capable of up to 530 hp. It is 70% larger than stock and can produce gains of up to 16 horsepower and torque. Users should see reductions of intake temperatures by as much as 30° under WOT. It is also great at recovering between WOT runs and during multi-gear pulls.

The Garret TMIC won’t offer the same performance as the GrimmSpeed, but it is considerably cheaper. It is a fantastic budget option for those looking to upgrade without breaking the bank. Used ones can often be had for only $400–500 in the classifieds.

3) WRX Cobb Tuning Front-Mount Intercooler

Price: $2,025.00

Design: Front-Mount

Our first front-mount intercooler on the list is the Cobb Tuning FA20 WRX Front-Mount Intercooler Kit. Cobb is an internationally acclaimed performance company, and they are probably the most well known manufacturer for Subaru performance parts. Lots of their popularity is due to their Accessport ECU tuner, but their hardware parts are also top notch. 

The Cobb WRX FMIC features a huge 24″ x 11″ x 4″ core with 2.5” piping. It is capable of absolutely massive horsepower gains,  but it still works efficiently on mid-range builds. It is compatible with the Cobb Big SF Intake only, so you have to get them as a package. Unlike many WRX FMICs, the Cobb unit does not require any modification to the bumper, only to the undertray on the WRX.

One of the biggest selling points for the Cobb front-mount is that it is 100% CARB compliant. Users can expect gains of as much as 45 horsepower with a tune, as well as a reduction in charge air temperatures to nearly ambient.

4) Subaru WRX GrimmSpeed FMIC

Price: $1,559.00 – $1,878.00

Design: Front-Mount

In addition to their TMIC, we also have GrimmSpeed FA20 WRX Front-Mount Intercooler Kit  on the list. It features a massive 27” x 11” x 4″ Cross Flow Core that can support small, medium, and big horsepower builds. The GrimmSpeed FMIC has the largest core available of all our listed intercooler kits. 

The GrimmSpeed front-mount intercooler will fit the FA20 WRX’s stock intake or the GrimmSpeed intake. Users can expect as much as 35–40 horsepower with an accompanying tune, as well as a reduction in intake temps by up to 40°. GrimmSpeed is known for their incredible fitment and workmanship, and their FMICs are top of the line.

5) WRX FA20 PRL Front-Mount Intercooler

Price: $1,295.00

Design: Front-Mount

The next entry on our list is the PRL FA20 WRX Front-Mount Intercooler Kit. PRL was one of the first companies to produce FMICs for the VA WRX, and their units are very well reviewed and have been used on many high horsepower builds. 

PRL’s FMIC measures to 22″ x 12″ x 3.5,” and is capable of producing as much as 600 horsepower. They claim some pretty incredible gains with their FMIC over the stock TMIC. Without a tune, they claim as much as 40 horsepower along with vastly improved midrange gains. With a tune and basic supporting mods, they claim as much as 60-75 horsepower over stock – though that’s a little bit more questionable. 

The PRL is the best bang for your buck FMIC on the list. It is the least expensive and still provides excellent gains, and it is recommended by many top tuners. Though they were discontinued for a few years, in early 2023 PRL announced they would be making more of them.

FA20 Subaru WRX Intercooler Upgrade FAQ

What is the WRX intercooler for?

The intercooler on the WRX cools the charge air that comes from the turbocharger before it reaches the engine. Intercoolers add horsepower and torque by increasing the oxygen level of the air passing through it.

Should I upgrade my WRX intercooler?

A WRX intercooler upgrade is a great mod to increase horsepower and torque, especially if you live in a warmer climate or use your WRX on the track.

How much horsepower will I gain upgrading my WRX intercooler?

Upgrading the WRX intercooler on the FA20 can add as much as 45 horsepower and 30 lb-ft of torque when combined with tuning.

Does an upgraded WRX intercooler need a tune?

No. Both top-mount and front-mount intercoolers can be run on the FA20 WRX without requiring a tune. However, without a tune the power benefits will not be as large.

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