For Subaru BRZ enthusiasts seeking a genuine power boost, the Mishimoto BRZ Turbo Kit stands out as a meticulously engineered solution. Forged from years of research and development, this kit transforms the naturally aspirated FA20 engine into a responsive, forced-induction powerhouse. While the installation requires mechanical confidence and attention to detail, the reward is a dramatic increase in horsepower and torque across the entire rev range. This guide walks you through each stage, from preparation and part removal to final assembly and leak checks, ensuring a safe and successful installation.

Important note: Adding a turbocharger to your Subaru BRZ significantly increases engine stress and heat. Proper tuning is absolutely required. This guide focuses on the mechanical installation; you must follow up with a professional ECU tune (e.g., using EcuTek or similar software) to ensure safe operation and optimal performance. Failure to tune can cause catastrophic engine damage.

What You Will Need: Tools and Components

Before lifting the hood, assemble everything you need. Scrambling for a missing tool mid-install not only wastes time but can lead to mistakes. In addition to the Mishimoto kit itself, gather these items.

Essential Tools

  • Metric socket set (3/8” and 1/2” drive, including 10mm, 12mm, 14mm, 17mm, 19mm)
  • Torque wrench (ft-lb and in-lb ranges)
  • Combination wrenches (10mm–19mm)
  • Allen keys and hex bits (for intercooler and charge pipe clamps)
  • Pry bar or flathead screwdriver (for hose removal)
  • Gasket scraper (for cleaning surfaces)
  • Jack, jack stands, and wheel chocks
  • Drain pans (for coolant and oil)
  • Shop towels and brake cleaner
  • Safety glasses, gloves, and a fire extinguisher

Supplies and Consumables

  • New engine oil and filter (high-quality 5W-30 or as recommended by tune)
  • Subaru long-life coolant (or equivalent) mixed 50/50 with distilled water
  • Thread-locking compound (medium strength, Loctite 242 or 243)
  • Anti-seize compound (for exhaust bolts)
  • Factory service manual or access to a reliable repair database

For reference, the official Mishimoto product page provides detailed component lists and torque specs: Mishimoto BRZ Turbo Kit. Always cross-reference with the latest version of the kit.

Understanding the Mishimoto BRZ Turbo Kit

The kit is designed as a complete, bolt-on solution that integrates with the FA20 engine without major fabrication. It includes:

  • Cast-iron turbo manifold with T3 flange
  • Ball-bearing turbocharger (typically a Garrett or precision journal bearing unit, check your specific kit)
  • Air-to-air intercooler with cast aluminum end tanks
  • Mandrel-bent charge pipes with silicone couplings
  • Oil and coolant supply lines with banjo fittings
  • High-flow intake system with MAF sensor housing
  • Downpipe and exhaust adapter
  • All necessary gaskets, bolts, and hardware

Take time to lay out every component and verify against the kit’s inventory sheet. Note that some modifications (like trimming the fan shroud or relocating the battery) were required on early revisions; confirm with Mishimoto’s latest instructions.

Preparation Steps

Proper preparation prevents poor performance. Work on a level surface, let the engine cool completely, and disconnect the battery (negative terminal first). This is critical for safety and to avoid short circuits.

1. Drain Coolant and Oil

Place drain pans under the radiator and oil pan. Carefully drain the engine coolant from the radiator petcock and the cylinder block drain plug (driver’s side, behind the exhaust manifold). Remove the oil drain plug and oil filter. Allow at least 20 minutes for complete draining. Reinstall the drain plugs with new crush washers (hand-tight plus torque to spec: oil pan 25–30 ft-lb, coolant plug 12–15 ft-lb).

2. Remove the Stock Exhaust System

Start at the rear: unbolt the catback section from the midpipe. Then unbolt the midpipe from the front pipe. Finally, remove the front pipe and the exhaust manifold. The manifold bolts are notoriously tight; use penetrating oil if needed. Set aside all bolts, as some may be reused.

3. Remove the Stock Intake System

  • Disconnect the mass air flow (MAF) sensor connector.
  • Loosen the clamps on the intake duct at the throttle body and airbox.
  • Remove the entire airbox assembly (two 10mm bolts at the top, plus a push pin at the bottom).
  • Set aside the intake tube temporarily—you may reuse the MAF sensor in the new intake.

4. Remove the Radiator Fan (if necessary)

On some vehicles, the intercooler piping may interfere with the driver’s side fan. Check clearance. If removal is needed, unbolt the fan shroud (two 10mm bolts at top, two at bottom) and carefully lift it out. Do not damage the fan blades or radiator fins.

Installing the Mishimoto Turbo Kit

With the engine bay clear of stock components, you can begin installing the turbo system. Work methodically and torque every fastener to the specifications provided in your installation manual.

5. Install the Turbo Manifold

Clean the cylinder head exhaust port surface with a gasket scraper and brake cleaner. Place a new manifold gasket over the studs. Fit the Mishimoto cast-iron manifold over the studs, ensuring it seats evenly. Tighten the nuts in a cross pattern to 25 ft-lb (or as specified). Do not overtighten—cast iron can crack if overstressed.

6. Mount the Turbocharger

Apply a thin coat of anti-seize to the studs on the manifold flange. Place a new gasket, then carefully slide the turbocharger onto the studs. Tighten the mounting nuts in two stages: first to 15 ft-lb, then to the final torque (usually 20–25 ft-lb). Spin the compressor wheel by hand to ensure it rotates freely with no binding.

7. Connect Oil and Coolant Lines

  • Oil feed line: Connect from the turbo’s oil inlet (top of the center housing) to the engine block oil supply port (usually a banjo bolt on the driver’s side of the block). Use new copper washers and torque the banjo bolt to 18–20 ft-lb.
  • Oil drain line: Attach the silicone hose from the turbo’s oil drain outlet to the fitting on the oil pan. This may require removing the pan and installing a weld-on -10AN bung (if not pre-drilled). Follow Mishimoto’s instructions precisely; an improper drain angle can cause oil smoke and seal failure.
  • Coolant feed and return: Connect the supplied hoses from the engine coolant outlets (e.g., the bypass pipe near the throttle body) to the turbo’s water ports. Use the supplied clamps and ensure routes are clear of hot surfaces.

Double-check all connections. A single loose fitting can result in oil starvation or catastrophic fire. For added safety, consider using thread-locker on banjo bolts that screw into aluminum.

8. Install the Intercooler and Charge Pipes

Mount the intercooler using the included brackets—typically two bolts on the radiator support. Ensure the intercooler sits level and does not contact the radiator fins. Connect the charge pipes: from the turbo outlet to intercooler inlet, and from intercooler outlet to throttle body. Use the high-quality silicone couplers and T-bolt clamps provided. Tighten clamps just enough to seal; overtightening can cut the silicone.

9. Reinstall or Upgrade the Intake System

Install the Mishimoto intake pipe. Transfer the MAF sensor from the original airbox to the new MAF housing included in the kit. Pay attention to orientation—the sensor must face the correct direction and sit flush against the rubber grommet. Reconnect the MAF electrical connector and the intake air temperature sensor if present. Secure the intake pipe with the supplied brackets.

10. Install the Downpipe and Reconnect Exhaust

Bolt the Mishimoto downpipe to the turbo exhaust outlet using a new gasket. Tighten the three 12mm bolts to 25 ft-lb. Attach the downpipe to the factory front pipe (or an aftermarket front pipe if you have one) using the supplied flex joint or adapter. Then reinstall the remainder of the exhaust system (midpipe, catback). Use new exhaust gaskets throughout to prevent leaks.

Final Assembly and Checks

Refill fluids: Fill the engine with new oil (approximately 5.5 quarts with filter change). Refill coolant using a funnel at the radiator cap. Run the engine without the cap to burp air bubbles. Top off as needed.

Reconnect the battery negative terminal. Cycle the key to the ON position (without starting) for a few seconds to prime the fuel pump. Check for any fuel, oil, or coolant leaks visually.

11. Start the Engine and Check for Leaks

Start the engine and let it idle. Listen for unusual noises—whistles, rattles, or ticking. Inspect all turbo oil and coolant lines, the manifold gasket, and the downpipe connection. If you see oil leaking from the turbo drain, you may need to adjust the angle. Shut off the engine if leaks are severe. For minor seepage, tightening banjo bolts may resolve it.

12. Verify Boost Gauge Function

If you installed a mechanical boost gauge (highly recommended), gently rev the engine to 2000–2500 RPM. The gauge should show slight positive pressure. Do not perform full-throttle runs until the vehicle is properly tuned—at least get a base tune loaded before driving.

13. Test Drive and Data Log

Take the car for a short, low-load drive. Monitor critical parameters: boost pressure, air-fuel ratio, oil temperature, and coolant temperature. If your ECU tuning solution supports data logging, capture a 10-minute cruise log and send it to your tuner. Avoid high boost or aggressive driving until the tune is finalized. A professional dyno tune is the safest way to unlock the full potential of the Mishimoto kit.

Important Tuning and Safety Considerations

The Mishimoto kit is well-engineered, but the FA20 engine has known weak points—particularly the connecting rods and ring lands when running high boost. Work with a reputable tuner who understands Subaru DI engines. Typical safe boost levels on a stock engine are 6–8 psi; with supporting fuel mods and careful tuning, some push to 10–12 psi. Always prioritize a conservative tune over chasing peak numbers.

For additional guidance, consult the FT86 Club forced induction forum and the Subaru performance tuning resources.

Troubleshooting Common Issues

Oil Smoke from Exhaust

Often caused by a kinked or blocked oil drain line. Ensure the drain hose has a continuous downward slope from the turbo to the oil pan. Also verify the turbo seals are not damaged during installation.

Boost Leaks

Use a smoke machine or pressure tester on the intake system. Common leak points: couplers not fully seated, loose MAF housing, or a torn gasket on the intercooler.

Check Engine Light

A CEL is expected until the ECU is reflashed. Common codes include P0171 (lean) and P0102 (low MAF voltage). These are resolved with proper tuning and MAF scaling.

Conclusion

Installing the Mishimoto BRZ Turbo Kit is a rewarding process that dramatically transforms the Subaru BRZ driving experience. By following this comprehensive step-by-step guide, you can complete the mechanical installation with confidence. Remember that the true performance depends on meticulous assembly, proper torque values, and—most importantly—a professional ECU tune. Take your time, double-check every connection, and enjoy the thrill of a turbocharged FA20 engine.