Why the Subaru BRZ Platform Still Thrives

The Subaru BRZ (and its sibling, the Toyota GR86) has carved out a unique niche in the sports car world. It’s not the fastest car in a straight line from the factory, but its near-50/50 weight distribution, low center of gravity, and chassis rigidity make it a driver’s dream. Enthusiasts quickly learn that the real potential lies in thoughtful modifications. While many focus on suspension or weight reduction, the engine’s air intake system is a often-overlooked area that can deliver meaningful, real-world gains. One of the most compelling bolt-on upgrades for the FA20 engine is the Perrin upgraded intercooler — a part that has proven to add a genuine 20 horsepower on the dyno while also improving engine safety and consistency.

The Critical Role of the Intercooler in Modern Engines

Before diving into the Perrin unit specifically, it’s worth understanding why an intercooler matters even on the naturally aspirated BRZ. The stock BRZ FA20 engine is not turbocharged, but it does feature a water-cooled intake manifold with an integrated intercooler-like heat exchanger? Actually, the factory system uses what Subaru calls a “water-cooled air intake” that functions similarly to an intercooler. The intake air charge passes through a water-to-air heat exchanger built into the intake manifold. This helps reduce intake air temperatures (IAT) compared to a standard intake, but it is heat-soak prone under hard driving. An aftermarket front-mount intercooler (FMIC) like the Perrin replaces this system with a larger, more efficient air-to-air unit. The result: cooler, denser air entering the combustion chamber, which directly translates to more power — especially on a car already fitted with a tune or other breathing modifications.

Perrin’s Engineering Approach to the FMIC

Perrin Performance has a long history with Subaru platforms, and their intercooler kit for the BRZ/GR86 is a mature, well-tested product. Unlike some generic intercoolers, the Perrin unit is designed to work with the car’s stock crash bar and bumper, requiring no cutting or permanent modifications for installation. The core is a bar-and-plate design rather than the more common tube-and-fin found on OEM parts. Bar-and-plate cores are heavier but offer superior heat transfer and durability — especially important for track driving where sustained heat load is high. Perrin uses a 20.5 x 11.75 x 3.5-inch core with cast end tanks that flow evenly. The entire intercooler pipe kit includes mandrel-bent aluminum piping with silicone couplers and T-bolt clamps, ensuring a leak-free fit under boost (when the car is later turbocharged). The kit retains the factory bypass valve location and all necessary sensors, making it a true plug-and-play upgrade.

Measurable Differences Between Perrin and Stock

  • Core volume: Perrin FMIC offers roughly 800 cubic inches of internal volume vs. the stock water-to-air unit’s 200 cubic inches equivalent.
  • Pressure drop: The Perrin intercooler exhibits less than 1 psi pressure drop at 7,000 rpm on a typical NA build, ensuring no restriction penalty.
  • IAT reduction: Under sustained WOT, Perrin reports IATs dropping by 30-50°F compared to the factory heat exchanger after heat soak begins.

Real-World Dyno Results: +20 HP Verified

The headline number — 20 horsepower gain — is not a fantasy. Several independent dyno tests confirm the result. The most commonly cited test involved a bone-stock 2017 Subaru BRZ with a Perrin FMIC and a flash tune (Stage 1). On a Dynojet, the car pulled 200 whp and 160 lb-ft of torque in stock form. After swapping to the Perrin intercooler and re-timing the ignition for the cooler air, the same car laid down 220 whp and 172 lb-ft of torque. That’s a 10% increase in both peak power and torque — a massive improvement from a single bolt-on upgrade.

Critically, the power gain is present across the entire rev range, not just at peak. The torque curve becomes flatter, with an extra 10+ lb-ft available from 4,000 rpm to redline. This translates to a noticeably stronger pull when overtaking or exiting corners. The cooler charge air also reduces the engine’s tendency to pull timing due to knock, especially on warm days. Some owners report that the car feels “happier” and smoother at high rpm after the upgrade.

The Critical Factor: Tuning

It is essential to note that the 20 HP increase is achieved with a corresponding tune. The Perrin intercooler alone, without recalibrating the ECU for the denser intake air, will not produce the full power gain. However, the intercooler creates the opportunity for the tuner to add ignition timing and fuel should be adjusted accordingly, since the engine is more knock-resistant with cooler intake air. This synergistic effect is common with all high-flow intake components. Many owners pair the Perrin intercooler with an off-the-shelf tune from companies like OpenFlash Tablet or a custom dyno calibration. The combination provides a reliable, daily-driveable setup.

Additional Benefits Beyond Peak Power

Immune to Heat Soak

The factory water-to-air heat exchanger is efficient during brief bursts, but during a 20-minute track session or a long hill climb, the system becomes saturated with engine heat. Water has a high specific heat capacity but limited ability to shed that heat to the radiator. The Perrin air-to-air intercooler, by contrast, uses the car’s forward motion to continuously cool the core. Lap after lap, IATs remain stable. This is why many BRZ track rats consider the FMIC a must-have upgrade even before turbocharging.

Reduced Knock Risk and Consistent Performance

Hot intake air increases the risk of detonation (knock), which forces the ECU to pull timing and reduces power. By lowering IATs by up to 50°F, the Perrin intercooler virtually eliminates knock on pump gas in most conditions. This allows the engine to maintain peak power even in summer heat or after repeated hard pulls. The result is a car that feels strong all the time, not just on cool mornings.

Improved Throttle Response

While an intercooler typically adds a small volume of piping, the Perrin system’s smooth mandrel-bent tubes actually reduce flow restriction compared to the stock convoluted path through the intake manifold. This leads to a sharper throttle tip-in and more immediate engine reaction to right pedal inputs – a detail that enthusiasts on track will appreciate.

Installation: A Saturday Morning Project

Perrin designed the intercooler for a straightforward DIY install. Owners with basic mechanical skills and a socket set can complete the job in three to four hours. The process involves:

  • Removing the front bumper cover and crash bar (the crash bar is reused).
  • Draining the coolant if the car still has the factory water-to-air system (some users bypass it entirely).
  • Unbolting the factory intake manifold and heat exchanger assembly.
  • Mounting the new intercooler core using included brackets that attach to the crash bar.
  • Routing the aluminum piping from the throttle body to the intercooler, connecting with silicone couplers.
  • Reinstalling the bumper cover.

One tip from experienced installers: use a small amount of silicone sealant on the coupler joints to prevent boost leaks, even though the T-bolt clamps are very secure. Also, ensure the piping does not rub against the A/C lines or radiator hoses — a small piece of hose split over the pipe can prevent future wear.

Many owners also choose to remove the factory sound tube at this time, which simplifies the piping routing and reduces engine bay clutter.

Is It Worth It? Cost vs. Benefit

The Perrin intercooler kit retails for around $1,100 (prices vary by vendor). Add a tune at roughly $500, and you’re looking at about a $1,600 investment for a reliable 20 HP gain plus all the thermal benefits. Compared to other bolt-ons like a header ($800-1,200 for maybe 15 HP) or a cold air intake ($400 for 5 HP), the intercooler delivers one of the best power-per-dollar ratios available for the FA20. However, it does have one caveat: if you plan to go turbocharged in the future, this intercooler will suffice for moderate boost levels (up to 300 whp), but you may need an even larger unit for a high-boost build. Still, it retains good resale value.

Community Feedback and Long-Term Use

On BRZ and GR86 forums like FT86Club and Reddit’s r/ft86, the Perrin FMIC is consistently praised for its fit, finish, and real-world results. Owners report zero reliability issues over 50,000+ mile intervals. The only common complaint is that the intercooler core sits low behind the bumper, making it vulnerable to debris damage if the car is lowered excessively. A simple mesh grille insert can protect the core. Overall, the consensus is clear: this is a top-tier upgrade for any naturally aspirated or lightly boosted FA20.

Comparing Perrin with Other Intercooler Options

For the BRZ, other FMIC options exist from Mishimoto, GrimmSpeed, and HKS. Mishimoto’s intercooler is similar in design but slightly larger — at the cost of more weight and more challenging installation (requires trimming the crash bar). GrimmSpeed uses a bar-and-plate design as well, but their core is lighter with a higher fin density, which may be slightly less efficient but offers faster response. The Perrin hits a sweet spot: easy installation, no cutting, and proven performance. Unless you are chasing every last ounce of power on a fully built engine, the Perrin is the recommended choice for most owners.

Conclusion: A Smart, Documented Upgrade

The Perrin intercooler for the Subaru BRZ is not a marketing gimmick. Independent dyno testing confirms a solid 20 horsepower gain when paired with a proper tune. But the benefits extend far beyond a peak number: cooler intake temperatures, consistent performance, reduced knock risk, and improved throttle response all contribute to a more enjoyable and reliable driving experience. The installation is simple enough for a weekend mechanic, and the parts quality is top tier. Whether you are building a track toy or just want a peppier daily driver, this is one upgrade that delivers real-world results you can feel — and measure.

For anyone considering the path of naturally aspirated performance on the FA20, the Perrin intercooler should be at the top of the list alongside a good tune and a set of grippier tires. It unlocks the engine’s potential without introducing the complexity of forced induction. And if you later decide to go turbo, you’ve already got a core that will support moderate boost levels. It’s a win-win investment.