exhaust-systems
How to Install a Corksport Exhaust on Your Nd Miata: Step-by-step Guide
Table of Contents
Why Choose the CorkSport Exhaust for Your ND Miata?
The Mazda MX-5 Miata ND is already a driver’s delight, but the factory exhaust leaves room for improvement in both sound and performance. The CorkSport cat-back exhaust system is engineered specifically for the ND platform, offering a deeper, more aggressive tone without drone on the highway, while also shedding weight compared to the stock system. In our experience, this is one of the best “first mods” for the ND — it’s reasonably easy to install at home, costs less than many competitors, and transforms the car’s character. Before you begin, understand that this guide assumes you are installing the CorkSport cat-back exhaust (part number A0-81000) or a similar variant. We’ll walk you through every step, from gathering tools to the final test drive.
Tools and Materials You’ll Need
Having everything ready before you lift the car ensures a smooth, frustration-free weekend project. Below is the complete list for this installation.
| Item | Notes |
|---|---|
| Socket set (metric, 10mm–14mm) | Deep sockets help with midpipe hanger bolts |
| Torque wrench (ft-lb and in-lb ranges) | Critical for final tightening |
| Ratchet and extensions | At least a 6″ extension |
| Jack and two jack stands (2-ton minimum) | Vehicles with low ground clearance may need low-profile jack |
| Safety glasses | Protect from falling debris and undercoating flakes |
| Mechanic’s gloves | Recommended for grip and cleanliness |
| CorkSport cat-back exhaust system | Check for all included hardware before starting |
| New exhaust gaskets | Factory gasket between header and midpipe; CorkSport includes new gasket |
| Anti-seize lubricant (copper or nickel) | Apply to all threaded fasteners |
| WD-40 or penetrating oil | May help loosen rusted bolts on older cars |
| Flat-blade screwdriver or trim tool | To release hanger bushings |
| Rubber mallet (optional) | For gentle persuasion of stuck hangers |
| Floor creep or cardboard | Comfort while working under the car |
For torque specifications, refer to the CorkSport installation instructions. Factory torque values for exhaust manifold to midpipe are typically 30–35 ft-lb; midpipe to muffler hangers are 10–15 ft-lb. We’ll note specific values in each step.
Preparation: Setting Up for Success
Park the Miata on a level, hard surface. The engine must be completely cool — exhaust components remain hot for over an hour after driving. If you’ve just driven the car, wait at least 90 minutes. Disconnect the negative battery terminal to avoid any electrical shorts when working near the rear of the car (the ND’s battery is in the trunk). Then, gather all tools and place them within easy reach under the vehicle.
One often overlooked step: remove the felt undertray at the rear of the car. The ND has a two-piece rear diffuser/aero panel that covers the exhaust tips and lower bumper. You’ll need to remove this before the stock muffler can slide out. Use a 10mm socket to remove the three plastic rivets (push-pins) along the lower edge and the two 10mm bolts at the sides. Set the diffuser panel aside carefully — the tabs are brittle.
Step 1: Lift and Secure the Vehicle
Use the jack to raise the rear of the car. Position jack stands under the factory lift points: the pinch welds just ahead of the rear wheels. Never rely on the jack alone. Shake the car after placing stands to confirm stability. For extra safety, chock the front wheels.
Step 2: Remove the Stock Exhaust
While the stock exhaust is one piece, it’s easier to disconnect it in sections. Start with the midpipe:
- Using a 12mm socket, remove the two bolts connecting the midpipe to the header (downpipe). The gasket will likely stay stuck to the header flange — gently pry it free, then discard.
- Locate the two rubber hangers supporting the midpipe. Use a flat-blade screwdriver to lever the hanger bushing off the metal peg. On older cars, apply penetrating oil and let it soak for five minutes.
- Slide the midpipe rearward to separate it from the muffler section. If stubborn, a rubber mallet tap on the muffler inlet will free it.
- Now move to the muffler. Remove the two 10mm bolts holding the muffler to the bumper hanger brackets (one per side). There are four rubber hangers total on the muffler (two above, two on the sides). Pop them all off using the same screwdriver technique.
- Lower the muffler carefully—the stock piece weighs about 24 pounds. Slide it out from under the rear bumper. The tailpipe will need to angle down and to the passenger side to clear the diffuser opening.
Caution: The stock exhaust may have accumulated heavy rust scale. Wear safety glasses and gloves when handling it. Dispose of the old system responsibly at a metal recycling center.
Step 3: Inspect and Prepare Mounting Points
With the factory exhaust removed, clean the header flange surface with a wire brush and brake cleaner. Check the studs and threads for damage. Apply a thin coat of anti-seize to all threads you’ll reuse — this prevents seizure in future removals.
Now is the perfect time to install new gaskets. CorkSport includes a high-quality graphite gasket that fits between the header and midpipe. Do not use the old gasket; it will leak. Also inspect the four rubber hanger bushings on the car. If they are cracked or brittle (common on 2016–2019 cars with higher mileage), replace them with OEM Mazda units (part number NAY9-40-030 for the muffler hangers).
Installing the CorkSport Cat-Back Exhaust
The CorkSport system is designed to be a direct bolt-on. It comes pre-assembled from the midpipe flange to the muffler, but you may separate them temporarily for easier installation — we recommend keeping it together if you can manage the weight (approximately 22 pounds total).
Step 4: Align and Hand-Tighten All Connections
- Slide the CorkSport system into position from the rear of the car. Guide the midpipe flange onto the header studs. Do not tighten yet.
- Loosely install the midpipe hanger bushings onto the chassis pegs. This helps support the weight while you align the muffler.
- For the muffler section, hook the four rubber hangers onto the corresponding metal tabs on the CorkSport muffler. The two upper hangers require you to lift the muffler slightly and push the bushing onto the car-side peg — use a trim tool to avoid pinching your fingers.
- Attach the two muffler-to-bumper bracket bolts (10mm) but leave them loose to allow adjustment.
- Reinstall the two bolts at the header-to-midpipe connection. Use the new gasket and torque to 30 ft-lb in a cross pattern. If your car has a rear O₂ sensor (CorkSport includes a bung plug if you don’t have one), transfer the sensor from the stock midpipe to the CorkSport bung — apply anti-seize to the sensor threads and torque to 20 ft-lb.
Step 5: Align the Exhaust Tips
This is the trickiest part. With all hardware hand-tight, step back and look at the tailpipe positions relative to the diffuser cutouts. The CorkSport tips should be centered and equally spaced on each side. Adjust the muffler by moving it left/right and rotating it slightly until the tips sit exactly as you want. Tip: place a piece of 1/8″ foam tape between the tip and diffuser to maintain a consistent gap while you tighten.
Once satisfied, tighten the muffler-to-bumper bolts to 15 ft-lb. Recheck tip alignment — if it shifts, loosen and repeat.
Step 6: Final Torque of All Fasteners
Use a torque wrench on every bolt:
- Header-to-midpipe flange: 30 ft-lb
- Midpipe hanger mounting bolts (if any): 12 ft-lb
- Muffler bracket to bumper bolts: 15 ft-lb
- Any band clamps supplied (CorkSport uses a slip joint with a clamp): torque to 25 ft-lb
Do not overtighten the band clamp — it can distort the pipe. After final torquing, wiggle each connection to ensure it’s secure.
Reassemble and Lower the Vehicle
Reattach the rear diffuser panel. Align the tabs into the bumper slots, then secure with the original 10mm bolts and push-pins. If any clips broke, replace them with OEM retainer part number N247-50-741.
Now lower the car from the jack stands. Remove the driver’s side jack first, then the passenger side, then lower the jack slowly. Reconnect the battery terminal and clean the terminal with a wire brush if needed.
Start-Up, Test Drive, and Final Checks
First Start: Start the engine and let it idle for 30 seconds. Immediately check for exhaust leaks by listening for hissing or blowing sounds at the header-to-midpipe joint. If you hear a leak, shut off the engine and retorque the flange bolts. Also check the O₂ sensor connection for error codes.
Warm-Up and Drive: Take the car for a 15-minute drive on varied roads. You’ll notice the CorkSport exhaust is louder at startup and under load, but it should not drone inside the cabin at highway speeds. After the drive, park on a clean surface and look for drips — water from condensation is normal; exhaust smoke is not. Let the system cool completely, then retorque the header flange bolts (they can loosen after the first heat cycle).
Maintenance and Long-Term Tips
- Check the midpipe and muffler hangers every oil change. Rubber bushings dry out over time and can cause rattles.
- Clean the exhaust tips with a dedicated metal polish (such as Mothers Mag & Aluminum Polish) every month to prevent corrosion.
- If you notice a drop in tone quality, inspect the internal packing of the muffler — CorkSport uses stainless steel wool, which may degrade after 50,000 miles. Replacement mufflers are available separately.
- For more aggressive sound, consider adding a CorkSport header or a tune. The cat-back alone provides a pleasant increase without being obnoxious.
Frequently Overlooked Details
- Rust Prevention: The ND uses a lot of aluminum, but steel exhaust bolts rust quickly. Apply anti-seize liberally. After installation, spray the underside of the exposed bolts with a corrosion inhibitor.
- Resonance: The CorkSport system is designed to avoid drone, but if you have an aftermarket sway bar or subframe brace, ensure that the midpipe does not contact the brace under hard cornering. A quick visual check with the car on ramps is enough.
- Sound in Different Driving Modes: On automatic ND models, the exhaust note is slightly muted compared to manual cars due to the ECU tuning. This is normal; a tune can help.
Conclusion: Enjoy the Rewards of a Well-Installed Exhaust
Installing the CorkSport cat-back exhaust on your ND Miata is a gratifying project that takes roughly 1.5 to 2.5 hours for a first-timer. The system not only sounds fantastic — a deep baritone without the rasp of some competitors — but also sheds over 8 pounds from the stock setup. More importantly, you’ve gained confidence working on your own car. Follow the instructions, take your time with alignment, and you’ll be rewarded with a more engaging Miata every time you press the start button.
For further reading, check out the Miata.net community discussion on this exhaust and the official CorkSport installation PDF. Happy driving!