Upgrading the exhaust system on your Mazda Miata (MX-5) is one of the most rewarding modifications you can make. A quality cat-back exhaust not only liberates a few horsepower but transforms the car’s character with a richer, more engaging exhaust note. Among the top-tier options on the market, the Remus cat-back exhaust stands out for its precision engineering, deep tone, and European craftsmanship. This guide provides a comprehensive, step-by-step walkthrough for installing a Remus cat-back exhaust on any generation of Miata. Whether you own an NA, NB, NC, or ND, the principles remain the same, though minor differences in pipe routing and hanger locations may apply.

Tools and Materials

Before you begin, gather the following tools and supplies. Having everything on hand prevents mid-job trips to the hardware store and ensures a smooth installation.

  • Remus cat-back exhaust system – Verify that the system is specifically designed for your Miata’s year and model. Remus uses laser-cut stainless steel and robotic welding, but fitment varies by chassis.
  • Socket set – Metric sockets from 10mm to 17mm, including a 14mm for the flange bolts and 12mm for hanger bolts. A 3/8‑inch drive ratchet with a breaker bar helps with stubborn fasteners.
  • Wrench set – Combination wrenches in the same sizes for hard-to-reach nuts.
  • Jack and jack stands – A low-profile trolley jack works best for Miatas. Two sturdy jack stands rated for at least 2 tons each. Never rely on a jack alone.
  • Rubber mallet – Useful for persuading rusted hangers or stuck exhaust sections.
  • Exhaust hanger removal tool – A set of dedicated exhaust hanger pliers (often called “snap ring pliers for exhaust”) makes disconnecting rubber isolators much easier.
  • Penetrating oil – WD‑40 Specialist or PB Blaster to loosen corroded nuts and bolts. Apply 15 minutes before starting.
  • Safety goggles and gloves – Keep debris and rust out of your eyes; cut-resistant gloves protect your hands.
  • Anti‑seize compound – Copper‑based anti‑seize for the flange bolts and hanger studs to prevent future corrosion.
  • Torque wrench – A 1/2‑inch drive torque wrench capable of 25‑50 ft‑lbs for flange bolts (check Remus instructions).

Preparation and Safety

Choose a flat, well‑ventilated workspace. Park the Miata on level ground, engage the parking brake, and chock the front wheels. Allow the engine and exhaust system to cool completely – exhaust components can exceed 400 °F and cause severe burns. Remove any loose items from the trunk or cabin that might be jostled while working. Have a fire extinguisher rated for Class B (flammable liquids) and Class C (electrical) nearby. If possible, run a shop vacuum to clear debris from around the exhaust tunnel – dust and rust can fall into your eyes.

Lifting the Vehicle

Position the jack under the rear differential or the factory‑designated lift points on the unibody frame rails. Raise the rear of the car until the tires are about six inches off the ground, then place jack stands under the rear subframe. Verify stability by gently shaking the car. For added safety, slide a second pair of jack stands under the front pinch welds to level the car – this also gives easier access to the mid‑pipe section.

Step 1: Remove the Stock Cat‑Back Exhaust

Start by spraying penetrating oil on the four flange nuts connecting the mid‑pipe to the catalytic converter, as well as the bolts that hold the exhaust hangers to the rubber isolators. Wait five minutes for the oil to work.

Disconnect the Flange

Using a 14mm socket, loosen the two bolts (or nuts and studs) at the flange joint between the catalytic converter and the factory mid‑pipe. If the car is older, these bolts may be severely rusted. Use a breaker bar and apply steady, even pressure. If a bolt feels like it might strip, apply more penetrating oil and tap it with a hammer. In extreme cases, a nut splitter or angle grinder may be necessary – but this is rare on well‑maintained Miatas. Once loosened, remove the nuts and set them aside. The flange will separate with a gentle pry from a flat‑head screwdriver.

Detach the Hangers

Slide the exhaust hanger removal tool over each rubber isolator and compress the tool to release the metal hanger rods. Work from the rear muffler hangers forward. On NB and ND models, there may be a fourth hanger near the differential. Remove all isolators carefully – they are reusable if not cracked or brittle. If an isolator is torn, replace it now; aftermarket polyurethane isolators offer longer life and better vibration damping.

Remove the Old Exhaust

With all hangers free, support the midsection of the exhaust and slide it out from under the car. The stock system comes out as one long piece on most Miatas, though some models may require removing the muffler separately. If the pipe doesn’t clear the axle, gently lower the rear of the car onto the jack stands (just an inch) to change the angle. Use a rubber mallet to tap the hangers free if they are stuck. Avoid hammering on the pipe itself – you can damage the catalytic converter or oxygen sensors.

Step 2: Inspect and Prepare the Remus Exhaust

Unbox the Remus system and lay all components on a clean tarp. Verify the contents against the included parts list: typically a muffler assembly, mid‑pipe, clamp kit, new gasket for the catalytic converter flange, and hardware packet with bolts, nuts, and washers. Check for any visible damage from shipping – rare but possible. Familiarize yourself with the alignment of the pipes. Remus exhausts are mandrel‑bent for consistent diameter, but the hanger tabs must align with the factory isolator positions.

Apply Anti‑Seize

Coat the threads of all new bolts with anti‑seize compound. This simple step prevents galling of stainless steel threads and makes future removal effortless. Also apply a thin layer to the inner face of the flange gasket (both sides) to ensure a perfect seal.

Step 3: Install the Remus Cat‑Back System

Position the Mid‑Pipe

Start at the front: slide the Remus mid‑pipe into position, aligning its flange with the catalytic converter outlet. Insert the new gasket between the flanges. Hand‑tighten the two bolts to hold the pipe in place – do not fully torque yet. If the mid‑pipe has an integrated resonator, ensure it does not contact the transmission tunnel or the rear subframe. Slight adjustments in rubber‑hanger orientation can provide clearance.

Attach the Muffler

Next, fit the muffler assembly. Slide the muffler inlet over the outlet end of the mid‑pipe. On Remus systems, the connection uses a V‑band clamp or a two‑bolt flange. Tighten the clamp or bolts firmly by hand – final tightening comes after all components are hung. Then attach the muffler to the rubber isolators using the new hanger rods provided. Apply a bit of soapy water to the isolators to ease insertion. Listen for any metal‑on‑metal contact: the muffler should be suspended without touching the bumper lip, spare tire well, or sway bar.

Secure All Hangers

Install the remaining hangers – there will be one or two on the mid‑pipe and one on the rear section. Double‑check that all rubber isolators are fully seated and that the metal hanger rods are not twisted. A twisted hanger will cause an exhaust leak over time.

Torque the Flange Bolts

Now go back and tighten the catalytic converter flange bolts to the manufacturer’s specification – typically 25–30 ft‑lbs for mid‑pipe to cat. Use a torque wrench to avoid stripping the threads in the converter flange. If your Remus kit uses a different flange style (e.g., a spring‑loaded clamp), follow the included instructions. Similarly, tighten the muffler mid‑pipe connection to the recommended torque.

Step 4: Final Checks Under the Car

With all connections torqued, visually inspect the entire exhaust path. Look for any point where the pipe touches the car body, suspension components, or the driveshaft. The exhaust must have at least ½ inch of clearance everywhere. Common contact points: the PPF (Power Plant Frame) brace on NB models, the lower control arm on NCs, and the rear shock tower brace on NDs. If you hear or see contact, loosen the hangers and reposition the pipe. Sometimes rotating the muffler a few degrees solves the issue.

Check for Leaks

Before lowering the car, start the engine briefly while still on jack stands (ensure nothing is in the way of the wheels). With a gloved hand, feel around each flange and the muffler connections for escaping air. Listen for hissing or ticking sounds that indicate a leak. Shut off the engine and tighten any suspect joints. It is normal for a small amount of white smoke to appear from the exhaust on the first start – that is manufacturing oils burning off.

Lower the Vehicle

Turn off the engine, raise the car slightly to remove the jack stands, and lower it to the ground. Then do a final visual inspection from the rear – check that the exhaust tips are centered in the bumper cutout and not pointing downward. Remus tips are adjustable; loosen the set screw and rotate the tip to align it perfectly.

Step 5: First Drive and Break‑In

Start the Miata and let it idle for a minute while monitoring the exhaust smell and sound. Do a thorough walkaround to ensure nothing is leaking. Then take the car for a gentle 10‑minute drive, varying RPMs but avoiding full throttle. The Remus exhaust will sound slightly louder and may drone at certain RPMs initially; this settles as the packing material “beds in” over the first 200 miles. After the break‑in period, the tone becomes deeper and more refined. Re‑torque the flange bolts after the first heat cycle – the gasket compresses slightly.

Performance and Sound Characteristics

The Remus cat‑back exhaust offers a pronounced improvement over stock: a throaty, European‑inspired note without excessive rasp or drone. On naturally aspirated Miatas, expect a modest gain of 3–5 horsepower at the top end, largely from reduced backpressure. On turbocharged cars, the gain is more significant. Remus uses Helmholtz resonators in many of their designs, which cancel specific frequencies to eliminate drone at highway speeds. Owners report that the exhaust is civil enough for daily driving yet aggressive enough for weekend canyon runs. For an even more focused sound, pair it with a Remus downpipe or header (check local emissions laws).

Common Installation Issues and Solutions

  • Rusted flange bolts – Use a hex‑head socket on a breaker bar with a cheater pipe. If rounding occurs, try a six‑point impact socket. Worst case, cut the bolt head off with a reciprocating saw.
  • Hanger isolators won’t budge – Apply silicone‑based lubricant to the rubber. The exhaust hanger removal pliers are essential; if you don’t have them, use a long screwdriver to pry the rubber loop open.
  • Exhaust tip hits bumper – Loosen the muffler hangers and slide the exhaust rearward slightly. Alternatively, adjust the tip angle with the set screw. If still touching, trim the bumper plastic with a Dremel, but do so cautiously.
  • Drone after installation – Let the exhaust settle for 200 miles. If drone persists, verify that no heat shield is rattling against the pipe. Sometimes adding a resonator to the mid‑pipe helps – Remus offers optional resonators for some models.

Maintenance and Long‑Term Care

Stainless steel exhausts like the Remus are highly corrosion‑resistant, but salt and road grime can still stain the finish. Wash the exhaust regularly with a mild soap and water, then wipe with a stainless steel polish. Every 12 months, check the hangers for cracking and the clamps for tightness. If you drive in winter regions, consider applying a thin coat of anti‑seize on the flange bolts before each winter season – it saves huge headaches later.

Why Choose Remus?

Remus has been manufacturing exhaust systems since 1990 and is a leading OEM supplier for European automakers. Their Miata systems are crafted from T304 stainless steel, with fully robotic TIG welding and a million‑cycle durability test. Unlike budget exhausts, Remus includes precise fitment, a balanced sound profile, and a warranty. Many owners find that the installation is straightforward enough for a weekend DIYer with intermediate mechanical skills.

For further reading, check the Remus official site for model‑specific instructions and sound clips. The Miata community also offers extensive installation logs – the Miata.net forum has hundreds of threads covering cat‑back upgrades. If you’re looking for performance comparisons, Flyin’ Miata publishes dyno charts for many exhaust systems, including Remus, giving you real‑world power numbers.

Conclusion

Installing a Remus cat‑back exhaust on your Miata is one of the most satisfying upgrades you can perform. The process is well within the reach of an average home mechanic, requiring only basic tools and a few hours of work. The reward is a more thrilling drive every time you turn the key. By following the steps detailed here, paying careful attention to alignment and torque, and allowing the system to break in, you will enjoy many years of improved sound and performance. Remember to work safely, keep your tools organized, and never compromise on the quality of your installation – your Miata will thank you.