How to Swap an Exhaust - Mazda Miata ND

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How to Swap an Exhaust - Mazda Miata ND

Written By: Gibson Hull
October 30, 2025

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Est. Completion Time: 2-3 Hours

Tools Required:

-Stage 01 Tools:
-Combination wrench set
-Socket set
-Screwdrivers
-Picks
-Pliers
-Safety glasses
-Gloves
-Flash lights
-Jack
-Jack stands
-Dead blow hammer
-Impact wrench
-Impact ratchet wrench

Parts Required:
-Exhaust System
-Exhaust Hangers

My dad loves cars. He drove Mustangs, Scouts, Subarus, Toyotas, and Ford pick-ups. But the two cars he always seemed to miss most were a couple of Toyota MR2s he had in the late 80’s and early 90’s. He had endless stories about how well they handled, how fun they were to drive, and how much you got out of them below the speed limit. A little racecar car you could actually use and drive every day. When the time came for him to pick up a new set of wheels, he started poking around on the used market for an old MR2. Given the market, and the need for something reliable to get to work, he slowly narrowed down to the more modern Toyota GR86 and the Mazda Miata MX-5.

We found him a 2017 ND Miata for an incredible deal. 2 owners, from far West Texas (zero corrosion), and in fantastic shape. It had average wear and tear and plenty of room to improve. The one immediate draw back for him was the exhaust. The short term previous owner installed an extremely loud aftermarket exhaust system. It was high quality, but the sound was far too loud. He immediately purchased a replacement. One that would drop the decibels significantly, but still keep the improved flow and performance. It was time for an exhaust swap.

Fig. 1: The author and the exhaust.

Part 01 - The Setup

Step 01. Gather your tools. To accomplish this job we collected the tools my dad had handy in his garage. Sockets and wrenches, jacks and jack stands, your basic Stage 1 Tools is all you need for this job. We also had his impact drill to speed things up and ran to the store for an improved car jack given how low the Miata sat, and how high we needed to lift it.

Step 02. The new exhaust. The exhaust that came on his car was an Invidia N1 catback exhaust. Catback means that the upgrade only replaces the exhaust system from the stock catalytic converters and back. I was impressed with the quality of the exhaust itself, and after some research we ended up choosing the Invidia Q300 catback to replace it.

Step 03. Measure the exhaust decibels. The Invidia N1 that is installed on the car made 106.8 decibels at idle after the Miata had time to warm up and smooth idle. It was much louder on cold starts, and painful on long drives. Keep reading for a comparison with the Invidia Q300 at the end of the post.

Step 01: Gather your tools.

Step 03: Measure the exhaust decibels.

Step 04. Chock the rear tires. After finding a nice flat surface, we used some 4x4 pieces of wood my dad had lying around to chock the rear tires so we could ensure the car did not roll when we lifted the front end up in the air. You can also use purpose built wheel chocks which are a bit better for this.

Step 05. Locate your the central jacking point. You can use your owners manual, service manual, or the internet to find the front central jacking point. We used the central front jacking point so that we could place jack stands under the two side jacking points. If we were to start with the side jacking points, there would be no room to place jack stands with the jack in the way. The Miata is a unibody construction, meaning the entire body of the car is the frame. Old cars are a bit easier to lift because with a separate frame and body lifting with the frame was straight forward. Most modern cars except some pick-ups and SUVs are built out of only sheet metal all welded into a one piece solid structure. That means you need to ensure that you lift the car in designated places to avoid crushing sheet metal that is not intended to hold the weight of the car.

Step 06. Jack up your car. With the right jacking point located we jacked up the car.

Step 07. Place jack stands under the designated points and lower the car. The Jack stands can go under the side jacking points. These are the jacking points you use to change a flat tire on one corner, and are designed to hold the weight of one corner of the car.

Step 08. Repeat the process on the rear. Find the rear central jacking point, lift the car, place jack stands under the side jacking points, and lower the car onto them.

Step 04: Chock the rear tires.

Step 05: Locate the front central jacking point.

Step 06: Jack up your car.

Step 07: Place jack stands under designated points and lower the car.

Step 08: Repeat the process on the rear.

Step 09. Spray all bolts with rust penetrant. Now that we have access to the underside of the car, we want to spray any bolts we need to remove with a good penetrating fluid, which is designed to get between the gaps and threads and help rusty or stuck bolts come free. It is not uncommon for exhaust bolts to be extremely stuck in place.

Step 10. Remove anything in the way of the exhaust. On the Miata, there are a couple of cross members we need to pull out of the way to be able to drop the exhaust.

Step 11. Remove the rear O2 sensor. There is an O2 sensor that measures exhaust gases after they flow through the catalytic converter. Sometimes you need a special tool to remove, but in this case, just unplug it and loosen with the right size wrench.

Step 12. Unbolt the old exhaust. Now you can access and unbolt the old exhaust. They are installed in a number of different ways but typically they go together with a couple of bolts at a few flanges down the length of the exhaust.

Step 13. Remove exhaust hangers from mounts. Exhaust hangers can be tricky. Typically they are made of rubber and allow the exhaust to hang from the car securely, but limit vibration as the engine and exhaust move freely from the car while running. There are only a couple on the Miata. The exhaust hanger tool is irreplaceable in my tool box. It saves so much time removing exhaust hangers without sometimes hours of fighting. A bit of silicone spray can help them slip off even faster. Be careful, the exhaust can be heavier than expected! Especially lying on your back under the car.

Step 09: Spray all bolts with rust penetrant.

Step 10: Remove anything in the way of the exhaust.

Step 11: Remove the rear O2 sensor.

Step 12: Unbolt the old exhaust.

Step 13: Remove exhaust hangers from mounts.

Step 13 (cont.): The exhaust hanger removal tool.

Step 14. Compare old and new and start bolting the new exhaust together. With the old exhaust out, we laid them side by side to ensure everything lined up similarly. Now we can start bolting the new exhaust together. Because the rear muffler on the new exhaust is heavier, we hung it in the car and bolted it up after the main length of exhaust was installed.

Step 15. Install the new exhaust. I hung the middle section of exhaust pipe on the middle exhaust hangar, then lifted the front into place and installed the front bolts.

Step 16. Install the new rear muffler. To get the rear muffler installed, it took some creative acrobatics. It was cumbersome, and required propping it into place with a bucket and pieces of wood. Then I could get an exhaust hanger or two on. Finally I could use my knees to shift around the muffler to line up the bolts and cinch them down.

Step 17. Fully tighten everything down, reinstall O2 sensor, and all crossmembers. Now go through and tighten every exhaust bolt properly with it all in place. Replace everything else you pulled off that was in the way or attached to the exhaust including the cross members and the rear O2 sensor.

Step 14: Compare old and new and start bolting the new exhaust together.

Step 15: Install the new exhaust.

Step 16: Install the new rear muffler.

Step 16 (cont.): Install the new rear muffler.

Step 17: Fully tighten everything down, reinstall O2 sensor, and all crossmembers.

Step 18. Install temporary exhaust hanger. Unfortunately one of the exhaust hangers was cut in half. It appears the previous owner did not want to fight with the ones they did not need for the old exhaust and cut them out instead of removing them. This coat hanger wrapped around the two hanger mounts did the job long enough for us to swing by the parts store on our test drive and pick up a new exhaust hangar to install in the parking lot.

Step 19. Lower the car back down and check out your new exhaust tips. Looking clean!

Step 20. Check the new decibel reading and compare. After another cold start and letting the car warm up and idle down, our new idle decibel reading is 72.9. That is about a 34 decibel improvement! Not to mention this exhaust is as quiet as stock but the tone is so much better. What a win all around.

Step 18: Install temporary exhaust hanger.

Step 19: Lower the car back down and check out your new exhaust tips.

Step 20: Check the new decibel reading and compare.

Part 03 - The Result

Step 21. Enjoy. The Miata with the new exhaust is so much more bearable and still sounds awesome. No more angry neighbors and a quality upgrade that will improve driving performance for years to come. Anyone can do this. Now you can surprise your parents’ by swapping their exhausts to something with a bit more pep.

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Step 21: Enjoy.