Unlocking the FA24’s Potential with a Cold Air Intake

The Subaru BRZ (second generation, 2022+) and its Toyota GR86 sibling are powered by the naturally aspirated FA24 engine, a 2.4-liter flat-four that inherits the boxer layout from its predecessor while adding substantial displacement and torque. While the FA24 delivers a healthy 228 horsepower from the factory, the intake system is designed for NVH reduction and packaging efficiency rather than maximum airflow. Replacing the restrictive stock airbox with a properly engineered cold air intake like the Mishimoto unit is one of the most cost-effective bolt-on modifications available.

The Mishimoto Cold Air Intake for the BRZ/GR86 FA24 is engineered to reduce intake restriction, lower intake air temperatures, and produce a more aggressive induction sound. Independent dyno testing has shown gains of up to 15 wheel horsepower and 12 lb-ft of torque when paired with a quality tune (or even without tuning on the stock ECU, though calibration is recommended for maximum benefit). This article covers the complete installation process, critical torque values, tuning considerations, and long-term maintenance tips so you can safely and confidently install the system yourself.

Why Choose the Mishimoto Cold Air Intake for Your FA24?

Not all cold air intakes are created equal. Mishimoto has developed a reputation for using high-quality materials and rigorous testing protocols. The BRZ/GR86 kit features a mandrel-bent, TIG-welded aluminum intake tube with a smooth internal finish that minimizes airflow turbulence. The large, oiled cotton filter element offers high flow rates while still providing effective particulate filtration. The heat shield is constructed from powder-coated 16-gauge steel with a closed-cell foam gasket that seals against the hood, isolating the filter from hot engine bay air. Additionally, the kit includes a billet aluminum MAF sensor housing with a precise fit to maintain accurate air-fuel ratio readings.

Expected real-world gains typically fall between 10–15 whp on a stock FA24, with the peak occurring in the mid-range (3,500–5,500 rpm) where the stock intake is most restrictive. Drivers also report improved throttle response and a deeper, more resonant intake note under hard acceleration. For those planning to add a cat-back exhaust or a tune later, this intake creates an excellent foundation.

Key Specifications

  • Filter Type: Oiled cotton gauze (reusable)
  • Tube Material: 6061 aluminum, mandrel-bent
  • Heat Shield: 16-gauge steel with foam gasket
  • MAF Housing: Billet aluminum, CNC-machined
  • Claimed Horsepower Gain: Up to 15 whp (with custom tune)
  • Fitment: 2022+ Subaru BRZ / 2022+ Toyota GR86

Tools and Materials You’ll Need

Before diving into the installation, gather the following tools. Having everything ready will prevent unnecessary interruptions and keep the job moving smoothly.

  • 3/8″ or 1/2″ drive socket wrench set with 8mm, 10mm, 12mm, and 13mm sockets
  • Flathead screwdriver (medium size)
  • #2 Phillips screwdriver
  • T25 Torx bit driver
  • Long-nose pliers (for hose clamps)
  • Rubber gloves (to keep oil off the MAF sensor)
  • Clean shop towels
  • Safety glasses
  • Penetrating oil (if fasteners are stubborn)
  • Digital torque wrench (5–50 lb-ft range) – optional but recommended

Also confirm that the Mishimoto kit includes all necessary hardware: intake tube, filter, heat shield, MAF sensor adapter, silicone coupler, hose clamps, zip ties (for the crankcase vent line), and installation instructions. It is wise to lay out the parts and verify the included hardware matches the instruction manual.

Preparation: Safety First

Working on any vehicle requires precautions. Set your BRZ on a level surface and engage the parking brake. If the engine has been running, allow it to cool completely – the intake manifold and throttle body can retain heat for up to an hour after shutdown. Disconnect the negative battery terminal using a 10mm socket and wait at least five minutes for the ECU capacitors to discharge. This prevents accidental electrical shorts and resets the ECU’s learned fuel trims, which will help the engine re-adapt to the new intake more quickly.

Place a shop towel over the exposed throttle body opening as soon as you remove the stock intake tube. Even a small drop or dust particle entering the intake manifold can cause scoring on the cylinder walls or valve seats.

Removing the Factory Intake System

The factory airbox on the FA24 BRZ is held in place by a combination of bolts, screws, and push-clips. Here is the step-by-step removal process.

Step 1 – Remove the Intake Duct and Airbox Cover

Start by unclipping the top cover of the stock airbox. Use a flathead screwdriver to pry up the two metal clips on the rear of the box. Lift the cover and set it aside. The filter element may come out with the cover or stay in the lower tray. Remove the filter and lower the tray.

Step 2 – Disconnect the MAF Sensor

Locate the mass airflow (MAF) sensor on the intake tube between the airbox and the throttle body. Depress the locking tab on the connector and pull gently to disconnect. Do not force the connector; if it feels stuck, use a small flathead to release the tab more fully. Wrap the connector in a shop towel to prevent contamination.

Step 3 – Remove the Intake Tube

Using a 10mm socket or flathead screwdriver, loosen the hose clamp securing the intake tube to the throttle body. Then loosen the clamp at the airbox end. Wiggle the tube free, rotating it slightly to break the silicone seal. Pull the tube out of the engine bay. Be careful not to drop debris into the throttle body opening.

Step 4 – Extract the Lower Airbox

Now remove the lower airbox housing. There are typically two 10mm bolts (one on each side of the box) and a third at the bottom. Use a ratchet with an extension to reach the lower one. If a bolt is difficult to remove, apply penetrating oil and wait a few minutes. Once the bolts are out, lift the airbox straight up and out.

Step 5 – Clean the Area

With the stock intake removed, wipe down the surrounding area with a damp shop towel. Remove any leaves, dirt, or debris that may have accumulated around the throttle body. Inspect the throttle body inlet for any carbon deposits. If you see significant buildup, consider a throttle body cleaning before proceeding (a dedicated cleaner and a soft brush work well).

Installing the Mishimoto Cold Air Intake

Now that the engine bay is ready, you can install the new system. Follow the order below to ensure proper alignment and secure connections.

Step 1 – Mount the Heat Shield

Place the Mishimoto heat shield into the engine bay where the stock airbox was located. Align the pre-drilled holes with the factory mounting points. Install the supplied M6 hardware (usually three bolts) and tighten to 6 lb-ft (8 Nm) using a torque wrench if available. Do not overtighten; the steel heat shield can distort if excessive force is applied. Ensure the foam gasket along the top edge is correctly positioned to contact the hood when closed.

Step 2 – Attach the MAF Sensor to the New Tube

The Mishimoto kit includes a billet MAF sensor adapter that replaces the factory MAF flange. Remove the MAF sensor from the stock tube (two Phillips screws) and carefully transfer it to the adapter. The sensor has a small arrow indicating airflow direction; make sure it points toward the throttle body. Secure the sensor with the provided flat-head screws and tighten them to 0.9 lb-ft (1.2 Nm) – basically snug by hand with a screwdriver. Use dielectric grease on the connector pins to prevent corrosion.

Step 3 – Install the Intake Tube

Slide the silicone coupler over the throttle body opening. Do not tighten the clamp yet. Slide the Mishimoto intake tube into the coupler, ensuring it seats fully. Rotate the tube so that the MAF sensor positioning aligns with the wiring harness without pulling or stretching the connector wire. Then tighten the coupler clamp to 3 lb-ft (4 Nm).

Step 4 – Secure the Intake Tube to the Heat Shield

The tube typically attaches to the heat shield via a metal bracket or rubber grommet. Align the tube bracket with the corresponding slot on the heat shield and press into place. If the kit uses a bolt, hand-tighten and then apply 6 lb-ft.

Step 5 – Install the Filter Element

Apply the provided hose clamp (non-marring style) loosely around the end of the intake tube. Slide the cotton filter onto the tube until it stops against the internal lip. Position the filter so it does not contact the heat shield or any adjacent components (allow at least 1/2-inch clearance). Tighten the clamp until it is snug but not crushing the filter neck.

Step 6 – Connect the Crankcase Vent Line

The stock intake system includes a small hose that routes crankcase vapors back into the intake tube. The Mishimoto kit will include a barb fitting and a length of hose. Attach the barb to the intake tube (or reuse the factory hose with a zip tie) and connect it to the crankcase vent port on the engine. Secure with a small hose clamp or zip tie. This step is often overlooked but is necessary to maintain proper crankcase pressure regulation.

Step 7 – Final Checks and Torque

Recheck all clamps, bolts, and electrical connections. Ensure the MAF sensor connector is fully seated and the locking tab clicks into place. Verify that the intake tube does not contact the hood, fuse box, or any moving parts. Gently rotate the filter to confirm it has clearance at all steering and suspension sweep angles. If everything looks good, proceed to reconnect the battery.

Post-Installation Steps

With the new intake installed, follow these final procedures to ensure everything operates correctly.

Reconnecting the Battery

Connect the negative battery terminal and tighten the nut to 5 lb-ft (6 Nm). Do not over-crank the terminal. Start the engine and let it idle for 1–2 minutes. The idle may be slightly rough initially as the ECU adjusts to the increased airflow. If the idle is unstable, check for vacuum leaks around the MAF sensor or coupler. A small puff of smoke from a smoke machine will reveal leaks – alternatively, spray carb cleaner around the joins (if idle changes, a leak is present).

Test Drive

After confirming no warning lights or strange noises, take the car for a 15–20 minute drive. Include a mix of city driving and moderate acceleration to allow the ECU to re-learn idle and part-throttle fuel trims. You should notice improved throttle response and a deeper induction sound above 3,500 rpm. The peak horsepower gain will be most apparent at higher RPMs. Keep the engine under 4,500 rpm for the first 50 miles to allow the MAF sensor to calibrate fully.

Break-In Period & Maintenance

The cotton filter element requires periodic cleaning and re-oiling (every 15,000–20,000 miles in normal conditions, more often if driving on dusty roads). Use a dedicated filter cleaning kit. Avoid over-oiling as excess oil can contaminate the MAF sensor, causing drivability issues. Check all clamps and bolts after 100 miles of driving, as vibrations can loosen them slightly.

Does This Intake Require a Tune?

The Mishimoto intake is designed to work with the stock ECU calibration. The FA24’s MAF sensor can compensate for the increased airflow to a certain degree. However, to fully realize the 15 whp gain, a custom tune (e.g., using ECUtek, Cobb Accessport, or open-source tuning) is highly recommended. A tune will optimize the air-fuel ratio, ignition timing, and throttle mapping for the new intake, resulting in smoother power delivery and potentially higher peak numbers. Even without a tune, expect a noticeable improvement in throttle response and induction sound.

If you do not plan to tune immediately, ensure you use high-octane fuel (91+ octane in the U.S.) to avoid knock events. Some owners have reported that the stock ECU takes 50–100 miles to fully adapt to the intake, after which the gains become more apparent.

Common Installation Pitfalls & Troubleshooting

  • Check Engine Light (CEL) After Install: Most common cause is a loose MAF sensor connector or a small vacuum leak. Double-check the connector clicks securely. Inspect the crankcase vent hose for cracks or poor fitment.
  • Filter Contacting Hood: If the filter rubs the hood liner, reposition the heat shield and tube to lower the assembly. Some owners add small washers under the heat shield mounts as spacers.
  • Unusual Whistling Noise: A high-pitched whistle at part throttle often indicates a small air leak at the MAF sensor gasket or coupler. Verify all clamps are tight and the MAF sensor is seated flush against the adapter.
  • Loss of Low-End Torque: This can happen if the intake tube diameter is too large for the stock tune. The Mishimoto tube is sized appropriately for the FA24, but if you experience a noticeable dip below 2,500 rpm, consider a tune with revised low-load fuel tables.

External Resources & Further Reading

For the official product page, detailed dyno charts, and warranty information, visit the Mishimoto website directly: Mishimoto Cold Air Intake for 2022+ BRZ/GR86.

If you are new to tuning the FA24, the FT86 Club FA24 Engine Tuning section offers community-sourced base maps and calibration advice tailored to this specific intake.

Finally, for torque specification reference and additional installation photos, consult the official installation manual PDF included with your kit or download it from Mishimoto’s support page. A full service manual for the Subaru BRZ is available through the Subaru Technical Information System (STIS) and is valuable for any longer-term projects.

Final Thoughts

Installing the Mishimoto Cold Air Intake on your FA24-powered BRZ is a rewarding project that delivers tangible performance benefits and a more engaging driving experience. With careful attention to detail during installation and a basic understanding of your engine’s needs, you can confidently unlock 10–15 horsepower in a single afternoon. The kit is well-engineered, the sound improvement is dramatic, and the potential for further gains with a tune makes it an ideal first step into performance modifications. Follow the steps outlined above, respect the torque values, and enjoy your faster, more responsive Subaru.