Enhancing the performance and acoustic character of your Toyota GR86 or Subaru BRZ is a deeply rewarding endeavor. Among the most impactful and satisfying modifications you can undertake is an aftermarket exhaust system. The Nakayama Motorsports exhaust has garnered significant attention within the GR86 community for its precision engineering, weight savings, and distinctive tone. This guide provides a comprehensive, authoritative walkthrough for installing a Nakayama Motorsports exhaust on your GR86. We will go beyond the basic steps, delving into advanced techniques, common pitfalls, and maintenance strategies to ensure your installation is both successful and long-lasting. Whether you are a seasoned DIY enthusiast or a first-time modifier, this expanded guide will equip you with the knowledge to perform a professional-grade installation.

Understanding the Nakayama Motorsports Exhaust

Before diving under your car, it is beneficial to understand what makes the Nakayama Motorsports exhaust a compelling choice for the FA24-powered twins. Nakayama Motorsports is known for developing performance parts that balance track-focused aggression with streetable refinement. Their exhaust systems for the GR86 are typically constructed from high-grade T304 stainless steel or titanium, offering significant weight reduction over the stock unit. The design philosophy focuses on optimizing exhaust gas flow while delivering a crisp, resonant sound without excessive drone.

Key Benefits of This System

  • Weight Reduction: The stock GR86 exhaust is notably heavy. A Nakayama exhaust can shed 15 to 25 pounds, improving power-to-weight ratio and reducing unsprung mass at the rear of the vehicle.
  • Performance Gains: While not a standalone power monster, the improved flow characteristics can unlock a few extra horsepower and torque, particularly when paired with a tune. The real-world benefit is often felt in throttle response and a smoother power delivery curve.
  • Sound Character: The Nakayama exhaust produces a deeper, more mature tone compared to the stock exhaust. It is designed to eliminate the flat note often associated with boxer engines, introducing a refined growl that builds cleanly to redline.
  • Build Quality: Expect precise welding, mandrel-bent tubing, and high-quality flanges and hangers. This reduces the likelihood of leaks and ensures a perfect fit.

For more details on the specific construction and sound profiles, you can visit the official Nakayama Motorsports website to view their product line for the ZN8/ZC8 chassis.

Tools and Materials Needed

Preparation is critical. Having the correct tools on hand will prevent frustrating interruptions. While the basic list is short, a few specialized items will make the job significantly easier.

  • Socket Set: A 3/8” drive set with metric sockets. Commonly needed sizes are 10mm, 12mm, 14mm, and 17mm. Deep sockets are helpful for exhaust manifold nuts if you are replacing the header section (though this guide focuses on the cat-back or axle-back).
  • Wrench Set: Combination wrenches in 12mm, 14mm, and 17mm are essential for holding bolts while loosening nuts.
  • Jack and Jack Stands: A low-profile floor jack and two reliable jack stands are non-negotiable. Never work under a car supported only by a jack.
  • Exhaust Hanger Removal Tool: This tool is invaluable. It allows you to safely stretch the rubber hangers without damaging them or the exhaust studs. Alternatively, a set of pliers with angled tips can work, but the dedicated tool is preferred.
  • Lubricant Spray: WD-40, PB Blaster, or a dedicated penetrating oil is essential for loosening rusted bolts and lubricating rubber hangers for easier removal.
  • New Exhaust Gaskets: The stock gaskets may be reusable, but installing new ones ensures a leak-free seal. Order gaskets for the specific mating points (e.g., catalytic converter to mid-pipe).
  • Safety Glasses and Gloves: Protect your eyes from falling debris and rust particles. Mechanic gloves will prevent cuts from sharp edges and keep your hands clean.
  • Ratcheting Combination Wrench or Flex-Head Ratchet: This can be a lifesaver when working in tight spaces near the rear subframe.
  • Breaker Bar: For stubborn bolts that are seized due to corrosion. A 1/2” drive breaker bar provides extra leverage.
  • Torque Wrench: Essential for tightening hardware to manufacturer specifications to avoid stripping threads or creating leaks.

Preparing Your GR86 for Installation

Proper preparation dictates the overall success of the job. Rushing this phase often leads to stripped bolts, damaged hangers, or even injury.

  1. Safe Environment: Park the vehicle on a completely flat, level surface. Concrete is preferable to asphalt for stability.
  2. Safety First: Engage the parking brake firmly. Place wheel chocks behind the front tires to prevent any movement.
  3. Battery Disconnection: Disconnect the negative battery terminal. While not strictly required for a cat-back exhaust, this prevents any accidental electrical shorts if your tools come into contact with the starter or other electronics.
  4. Cool Down: Ensure the exhaust system is cool to the touch. Working on a hot exhaust can cause burns and make rubber hangers brittle and difficult to remove.
  5. Lift the Vehicle: Using the jack, lift the rear of the car from the factory jack point behind the rear subframe. Place jack stands under the designated lift points on the rear pinch welds. Lower the car onto the stands and give the vehicle a firm shake to confirm stability.

Step-by-Step Installation Guide

This process is broken down into removal of the stock system and installation of the Nakayama system. Patience is key, especially with fasteners exposed to road salt and grime.

Removing the Stock Exhaust

  1. Apply Lubricant: Spray all exhaust hangers and the bolts connecting the exhaust flanges with penetrating oil. Allow it to soak for 5-10 minutes.
  2. Remove Exhaust Hangers: Using your hanger removal tool, carefully detach the rubber isolators from the metal studs on the chassis. Start at the muffler section and work forward. There are typically four hangers on the rear section and two on the mid-pipe.
  3. Disconnect Flanges: Locate the bolts connecting the mid-pipe to the catalytic converter. Use a socket or wrench to remove them. If they are extremely tight, use a breaker bar. Be prepared for the exhaust to drop slightly once the last bolt is removed.
  4. Lower the System: With all hangers and flanges disconnected, the stock exhaust should be free. Carefully lower it. It may be easier to remove the muffler section first, followed by the mid-pipe. The stock system is heavy, so have a helper or support jack ready.
  5. Clean Mating Surfaces: Use a wire brush or sandpaper to clean the flanges on the catalytic converter and the subframe hangers. Remove any rust or old gasket material to ensure a clean seal.

Installing the Nakayama Motorsports Exhaust

  1. Position the System: Slide the new Nakayama exhaust components under the car. For a cat-back system, start with the mid-pipe section. Place the new gaskets on the flange at the catalytic converter.
  2. Attach Mid-Pipe: Lift the mid-pipe into position and align it with the catalytic converter flange. Insert the bolts and hand-tighten them. Do not fully torque them yet.
  3. Attach the Rear Section: Connect the rear muffler section to the mid-pipe using the provided gasket. Hand-tighten these bolts as well.
  4. Reinstall Hangers: Lubricate the new hangers if necessary, and reattach them to the chassis studs. A little soapy water can help the rubber slide on. Ensure each hanger is fully seated and not twisted.
  5. Align the System: This is the most important step for preventing drone and rattles. With all bolts hand-tight, adjust the exhaust tips to sit evenly in the rear bumper cutouts. Check that the exhaust does not touch the subframe, sway bar, or heat shields. The system should have a consistent gap around the tips.
  6. Torque Bolts: Working from front to back, torque all flange bolts to the manufacturer’s specifications. A typical range for 12mm bolts is 30-35 ft-lbs. Check the Nakayama Motorsports instructions for exact values.
  7. Final Inspection: Wiggle the exhaust to check for interference. Ensure all clamps and bolts are tight.

Post-Installation Checks and Testing

After the exhaust is secured, your job is not over. A systematic check will save you from a re-do.

  1. Reconnect the Battery: Reconnect the negative terminal. Start the engine briefly to check for immediate leaks at the flanges.
  2. Listen for Leaks: With the engine running, use your hand (careful of hot surfaces) or a rag to feel for air escaping around the gaskets. A small leak will sound like a hiss or tick.
  3. Check Clearance: Turn the steering wheel fully from lock to lock. Check that the exhaust does not contact the steering rack or any suspension components. This is a common issue with improperly aligned aftermarket systems.
  4. Test Drive: Take the car for a short 10-15 minute drive. Listen for drone at highway speeds, rattles against the chassis, and ensure the exhaust tips do not vibrate against the bumper plastic. Drive over bumps and uneven surfaces to check for clearance.
  5. Re-Torque After Heat Cycle: After the first drive, allow the system to cool. Re-torque all flange bolts, as heat expansion can cause them to loosen slightly.

Maintenance and Longevity

A Nakayama exhaust is an investment. Proper maintenance will keep it looking and performing well for years.

  • Regular Cleaning: Road grime and brake dust can dull the finish. Use a dedicated metal polish or soap and water to clean the tips. For stubborn carbon buildup, a mild abrasive like a metal-safe scrubbing pad works well.
  • Inspect Hangers: Rubber hangers degrade over time. Check them every six months for cracks or fatigue. Replacing deteriorated hangers prevents the exhaust from sagging and causing stress on the flanges.
  • Check for Leaks: Annually, or after any track day, inspect the gaskets and flanges for signs of soot, which indicates a leak. Replacing gaskets is inexpensive and prevents noise and performance degradation.
  • Protect Against Corrosion: If you live in an area where roads are salted in winter, consider applying a high-temperature clear coat or ceramic coating to the exhaust to protect it from rust.

Troubleshooting Common Issues

Even with careful installation, issues can arise. Here are solutions to the most common problems.

  • Drone at Highway Speeds: This is often caused by the exhaust resonating at a specific RPM. Adding a Helmholtz resonator in the mid-pipe or wrapping the exhaust with heat tape can help. Also, re-check clearance; contact with the chassis can introduce resonance.
  • Rattling Sounds: Check for contact with the heat shields, sway bar, or subframe. A simple adjustment to the hangers or adding a thin rubber spacer can resolve this.
  • Difficult Hanger Removal: If the rubber hangers are stuck, apply more lubricant and use a pry bar carefully. Never yank on the exhaust tubes.
  • Leaking at Flanges: Ensure the gaskets are properly aligned and the flanges are flat. Over-tightening can warp the flange, causing a leak. Use a new gasket and follow the torque spec.

Frequently Asked Questions

Q: Will installing this exhaust void my warranty?
A: An axle-back or cat-back exhaust generally does not void the entire warranty. However, if the aftermarket part directly causes a failure, that specific repair may not be covered. It is best to consult with your dealership.

Q: Do I need a tune after installing a cat-back exhaust?
A: No. The stock ECU can compensate for the increased flow from a cat-back system. A tune is only recommended if you also add headers and a high-flow catalytic converter.

Q: How long does the installation take?
A: For a first-timer, expect 2 to 3 hours. Experienced mechanics can complete the job in under an hour.

Q: Can I install this on a stock GR86 without a lift?
A: Absolutely. With proper jack stands and sufficient clearance, all work can be completed while the car is safely elevated. For additional tips on safe lifting, consult a resource like Team JDMotorsports’ guide on safe car lifting.

Conclusion

Installing a Nakayama Motorsports exhaust on your GR86 is a hands-on project that delivers immediate and gratifying results. By following this expanded guide, you have moved beyond simple bolt-on instructions to understanding the principles of proper alignment, maintenance, and troubleshooting. The combination of a quality Nakayama system, meticulous installation, and ongoing care will elevate your driving experience. For further community insight and installation stories, the GR86.org performance forum is an excellent resource for peer advice and tips. Now, get out there and enjoy the sound of your build.