Why Upgrade the Intercooler on Your FA20 Engine?

The FA20 engine, found in the Subaru BRZ, Toyota 86, and Scion FR-S, is a high-revving, naturally aspirated 2.0-liter boxer four. While it’s a solid platform for both daily driving and track use, the factory intercooler (on turbocharged variants or after forced-induction conversions) is built to a cost and often becomes a bottleneck when you increase boost pressure or add a turbocharger. The stock intercooler’s core is thin, the end tanks are plastic, and the charge pipe routing is less than ideal for high-flow applications. Even on a naturally aspirated setup, many enthusiasts install a front-mount intercooler in preparation for future boost. Upgrading to a Perrin intercooler delivers lower intake air temperatures, reduced pressure drop, and improved heat rejection—all of which translate to more consistent power and greater engine reliability.

Perrin Performance has a reputation for manufacturing high-quality, direct-fit intercoolers specifically designed for the FA20 platform. Their units feature a cast aluminum end tank design that flows better than the stamped metal or plastic OEM parts, and a bar-and-plate core that sheds heat much more efficiently than the tube-and-fin OEM core. This guide will walk you through the entire installation process, from gathering the right tools to performing a final leak test, so you can enjoy a cooler, denser charge of air and the power that comes with it.

Tools and Materials Needed

Before you start wrenching, collect all the items listed below. Using the correct tools not only makes the job easier but also prevents damage to fasteners and components.

  • Perrin intercooler kit (ensure it includes the intercooler core, charge pipes, silicone couplers, T-bolt clamps, and all necessary hardware)
  • Socket set (metric, 8mm–22mm) with extensions and a universal joint
  • Combination wrench set (metric, 10mm–18mm)
  • Torque wrench (capable of 5–50 ft-lb, preferably a beam or click-type)
  • Flathead screwdriver (for prying hose clamps)
  • Phillips screwdriver (for any plastic trim fasteners)
  • Pliers (needle-nose and regular, for removing spring clamps)
  • Hose clamp pliers (optional but helpful for spring-type clamps)
  • Heat-resistant silicone couplers (included in the kit, but have spares if needed)
  • T-Bolt clamps (included, better than worm-gear clamps for boost applications)
  • Trim removal tool (to remove plastic under-tray and front bumper cover if required)
  • Safety goggles
  • Mechanic’s gloves
  • Shop rags and parts cleaner (to clean old gasket surfaces)
  • Anti-seize compound (for stainless steel fasteners)
  • Threadlocker (blue) (for critical mounting bolts)

Preparation Steps

Proper preparation sets the stage for a clean, safe installation. Follow these steps before you touch a single bolt:

  • Park on level ground and engage the parking brake. Chock the rear wheels for extra safety.
  • Disconnect the negative battery terminal (12mm socket). This prevents any accidental electrical shorts or unintended airbag deployment if you need to work near crash sensors.
  • Allow the engine to cool completely—at least 2–3 hours after a drive. The intercooler and charge pipes can get very hot; plus, you’ll be working near coolant hoses and the turbo which can cause burns.
  • Remove any engine covers or plastic shrouds that block access to the front of the engine bay. For FA20 platforms with a front-mount intercooler, you may also need to remove the front bumper cover or at least the upper grille to get full access.
  • Take a reference photo of the stock intercooler and hose routing. This will help you when installing the new unit, especially if your Perrin kit routes charge pipes differently.

Removing the Stock Intercooler

Whether you’re working on a factory turbocharged FA20 (e.g., the Subaru Levorg or aftermarket turbo kit) or a naturally aspirated engine with a standard front-mount intercooler, the removal process is similar. Here’s the step-by-step:

  1. Locate the stock intercooler—usually mounted low in the front bumper area, behind the grille. It will have two large-diameter hoses: one from the turbo (or compressor) and one leading to the throttle body.
  2. Loosen the hose clamps on both ends. Use a flathead screwdriver for worm-gear clamps or hose clamp pliers for spring clamps. Slide the clamps back along the hose to free them.
  3. Disconnect the inlet and outlet pipes: Carefully pull each charge pipe off the intercooler. A light twisting motion helps break any adhesion from residue or heat cycling. If the silicone is stubborn, use a plastic pry tool to separate them—never a metal screwdriver that could damage the aluminum core.
  4. Remove the mounting bolts. The stock intercooler is typically secured by two to four bolts (usually 12mm or 14mm heads) that attach to brackets on the crash bar or frame rails. Use your socket set with an extension to reach them.
  5. Lift the stock intercooler out from the bumper opening. You may need to tilt it to clear the fan shroud or condenser lines. Set it aside. If you plan to sell it or reuse it, store it in a safe, clean place.

Pro tip: If your vehicle has a front bumper cover with an integrated lower grille, you may need to remove the bumper to access the intercooler mounting area. Consult a factory service manual for your specific year. Removing the bumper is not always required on Perrin kits—their intercooler is designed to fit through the existing opening—but having the bumper off makes the job much easier.

Installing the Perrin Intercooler

With the stock unit out, it’s time to put in the Perrin intercooler. The kit is designed to be a direct replacement, but you must pay attention to alignment and fastener torque.

Positioning the Core

  1. Test-fit the Perrin intercooler before tightening anything. Insert it into the same location as the stock unit. The core should sit level, with the inlet and outlet ports pointing toward the driver or passenger side (depending on kit design).
  2. Align the mounting tabs on the intercooler with the factory brackets. Perrin includes precision-machined aluminum brackets that match the OEM mounting points. If your kit uses adapter brackets, attach them first to the intercooler, then to the car.
  3. Secure the intercooler with the bolts provided. Torque them to 15–18 ft-lb (check your specific kit’s instructions). Use a drop of blue threadlocker on each bolt to prevent loosening from vibration.
  4. Attach the silicone couplers to the intercooler ports first. Slide each coupler over the flared end of the core and position the T-bolt clamp about ¼ inch from the edge. Tighten the clamp lightly—just enough to hold it in place.

Connecting the Charge Pipes

The Perrin intercooler kit comes with mandrel-bent aluminum charge pipes that replace the restrictive factory rubber hoses. Follow these steps for a leak-free installation:

  1. Connect the outlet charge pipe (the one leading to the throttle body). Slide the pipe into the silicone coupler on the intercooler output. Ensure the pipe is fully seated (you should feel it bottom out). Tighten the T-bolt clamp to 4–5 ft-lb (snug).
  2. Route the inlet charge pipe from the turbo (or supercharger) to the intercooler inlet. On some FA20 configurations, you may need to remove the factory air box or battery tray to access the turbo outlet. Use the included brackets to support the pipe and prevent rubbing against the fan or radiator.
  3. Check clearance at the hood, fan shroud, and radiator. Rotate the pipes slightly if needed so they don’t contact anything when the engine rocks under load. Re-tighten all clamps once routing is perfect.
  4. Install the included MAP sensor bung if your kit has one (for aftermarket engine management). The bung typically screws into a boss on the charge pipe. Seal it with pipe thread compound or PTFE tape.

Common mistake: Overtightening the T-bolt clamps on aluminum pipes can deform the pipe or crack the coupler. Use a torque wrench or a short screwdriver handle to avoid overdoing it.

Final Steps and Testing

Now that the intercooler and charge pipes are physically installed, you need to ensure everything is sealed and ready for boost.

Leak Testing

  1. Visually inspect all connections. Double-check that each coupler is fully engaged (not half-off) and that no hose is kinked.
  2. Pressurize the system with a boost leak tester. You can build a simple one from a PVC pipe cap and a Schrader valve that fits into the turbo inlet hose. Or, use a smoke machine to spot leaks. If you don’t have either, listen for hissing while the engine is idling—but a boost leak test under pressure is far more reliable.
  3. Re-tighten any clamps after the leak test. Run the engine to operational temperature, then shut it off and re-check clamp torque. Thermal expansion can loosen them.
  4. Reconnect the negative battery terminal. Turn the key to the “ON” position (do not start) for 5 seconds to allow the ECU to re-learn the throttle position. Then start the engine.

Test Drive

  1. Let the engine idle for 2–3 minutes while you watch coolant temperature and listen for abnormal noises. Verify that the intercooler fans cycle on and off normally.
  2. Take a short, moderate test drive (10–15 minutes). Monitor boost pressure (if you have a gauge) to ensure it matches your tune. The Perrin intercooler should show similar or slightly lower boost psi due to reduced restriction—this is normal and will be compensated by your ECU or boost controller.
  3. Check for any warning lights. If the check engine light illuminates, read the code. Common issues: disconnected MAF sensor, boost leak lean condition, or incorrect charge pipe routing that disturbed the electrical harness.
  4. Log intake air temperatures (IATs) if you have a datalogger. You should see significantly lower IATs at the same ambient temperature compared to the stock intercooler, especially during repeated pulls.

Maintenance Tips

After the first 500 miles, re-check all T-bolt clamp torque and inspect the couplers for any signs of degradation. The bar-and-plate core can accumulate debris and insects; clean it periodically with a gentle water spray (avoid high-pressure washers near the fins). With proper care, your Perrin intercooler will deliver reliable performance for the life of the engine.

Why This Upgrade Matters for Reliability

Many enthusiasts focus solely on horsepower gains from an upgraded intercooler, but the real benefits are consistency and knock resistance. The FA20’s high compression ratio (12.5:1 in naturally aspirated form) makes it sensitive to intake air temperature. Hotter air promotes detonation (knock), which the ECU counters by pulling timing—losing power. A larger, more efficient intercooler keeps IATs close to ambient, even during repeated pulls on a hot day. This also reduces thermal stress on the turbocharger and allows you to run more aggressive ignition timing safely.

Perrin specifically designed their intercooler to be a direct fit without cutting or modifying the bumper beam. The cast aluminum end tanks are stronger than the factory plastic units, which can crack under high boost or at high mileage. The bar-and-plate core is less prone to damage from rocks and debris compared to the delicate tube-and-fin OEM core. All of this translates to a component that doesn’t just make power—it protects your engine from the most common failure modes of forced-induction systems.

Additional Resources

For further reading, check out the official Perrin product page for this intercooler: Perrin Performance. You can also find community install threads on the FT86 Club forums for year-specific tips. For tuning advice, consider contacting a reputable FA20 tuner like Delicious Tuning to optimize your ECU after the upgrade.

Conclusion

Installing a Perrin intercooler on your FA20 engine is one of the most effective bolt-on upgrades for improving both power and reliability. The process is straightforward if you have the right tools and follow a systematic approach: prepare, remove the stock unit, install the new core, route the charge pipes, and perform a thorough leak test. By keeping intake air temperatures low and reducing pressure drop, your engine will run stronger, safer, and more consistently. Whether you’re building a daily-driven sports car or a dedicated track machine, this upgrade delivers tangible, repeatable gains that you’ll feel every time you drive.