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 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, the OEM intercooler is a huge weakness.

An upgraded intercooler is one of the best performance upgrades for the WRX. In this guide we’re going to discuss the performance benefits of intercoolers, considerations between top mount and front mount options, and cover some common questions.

Subaru WRX Intercooler Upgrade Benefits

  • +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. 

WRX Front Mount vs Top Mount Intercoolers

For most builds, a top-mounted intercooler will be more than adequate on the WRX. 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. 

Even with the hood scoop, top-mounted intercoolers don’t even compete with WRX front-mount intercoolers. They are more expensive and some require some bumper modifications, but from a performance perspective front mount is the way to go.

Top Mount is Fine For Sub-500whp

For the vast majority of builds under 500whp, 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 these power levels since the hood scoop is very effective.

If you plan on surpassing the 500whp level then a front mount is a must. A front mount is a better upgrade regardless of power levels, it’s just a lot more expensive which is why we say it’s okay to stick with top mounts for lower power levels.

Frequently Asked Questions

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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