NC Miata Exhaust Upgrade Guide

Eiginber Belarmino
October 20, 2024

If you’re a Miata enthusiast looking to give your NC Miata some extra flair in terms of sound and performance, you’ve come to the right place! While the NC Miata is a fantastic car in its own right, many owners find the stock exhaust a little too quiet and unexciting. Upgrading your exhaust can dramatically enhance both the driving experience and the overall personality of your car. In this guide, we’ll take you through everything you need to know about the NC Miata’s exhaust system, discuss popular aftermarket options, and help you choose the best setup for your Miata.!

To really understand how aftermarket exhausts improve your car’s performance and sound, it helps to get a basic understanding of the stock exhaust system. The NC Miata’s factory setup is functional and keeps things smooth and quiet for daily driving, but it’s not designed to offer the aggressive tone or performance that many Miata enthusiasts crave.

Exhaust Manifold

The exhaust manifold in the NC Miata is made of cast iron, which is durable and does a great job of keeping noise levels low. Unfortunately, this design also adds unnecessary weight and restricts airflow, limiting the car’s performance. The manifold also includes a Warm-Up Three-Way Catalyst (WU-TWC), which helps control emissions by reducing harmful gases. This is an important feature for keeping the car emissions-compliant, but it can also be a bit of a bottleneck in terms of performance.

There are also lambda sensors—one upstream and one downstream—that monitor the air-fuel ratio and the performance of the catalytic converter. When you upgrade your exhaust manifold to an aftermarket option, you might notice that many of these setups eliminate the catalytic converter for increased flow and reduced backpressure, leading to significant performance gains. However, this may affect emissions, so it’s important to check local regulations before making the switch.

Mid-Pipe

Next up is the mid-pipe, which houses the secondary catalytic converter in the NC Miata. The secondary cat is essential for keeping emissions under control, especially if you’ve swapped out the primary cat in the manifold. The stock mid-pipe also features a resonator, which smooths out the exhaust sound to prevent it from getting too harsh or raspy.

When you start modifying your mid-pipe, you’ll typically find that aftermarket versions are either catless or use high-flow catalytic converters. Removing or upgrading the resonator can significantly change the sound profile of your car, making it louder and more aggressive. While this modification can lead to a more thrilling exhaust note, it may also make the car too loud for daily driving, so it’s worth considering your personal needs.

Back Box (Muffler)

Finally, we come to the back box, also known as the muffler, where most of the sound control takes place. The stock muffler is designed to keep noise levels low, which makes sense for a comfortable daily drive, but it doesn’t exactly give you that sporty sound.

Swapping out the muffler is one of the easiest ways to modify your Miata’s sound without affecting emissions or needing significant under-car changes. For many NC Miata owners, replacing the back box is a great first step toward a more aggressive exhaust tone, and it’s an entry-level modification that can make a big difference.

Cobalt Exhaust

If you’re looking for an affordable yet effective upgrade, the Cobalt exhaust is a solid choice. This system is known for being a “stock plus” option, meaning it offers a deeper, more refined tone than the factory exhaust without being obnoxiously loud. It’s perfect for daily drivers who want to enhance their Miata’s sound without going overboard.

The Cobalt system is constructed from stainless steel and features polished tips that add a nice visual touch to the rear of the car. Priced at around 238 pounds, it’s one of the more budget-friendly options on the market. While it doesn’t provide significant performance gains, it’s a great way to improve the sound profile of your Miata without breaking the bank.

Cobra Sport (Road and Race Versions)

Cobra Sport offers two versions of their exhaust system for the NC Miata: the Road version and the Race version. The Cobra Sport Road is a middle-ground option that’s slightly louder than the Cobalt, but still manageable for daily driving. It delivers a burbling growl that intensifies as you climb through the RPMs, and its larger diameter piping allows for better airflow compared to stock.

The Road version is constructed from high-quality stainless steel and is priced at around 525 pounds, making it a more expensive but worthwhile investment for those looking for improved sound quality and performance.

For those who want something even louder, the Cobra Sport Race version is the way to go. This setup produces a more aggressive exhaust note, especially at wide-open throttle. It’s ideal for track days or performance-focused builds, but may be a bit too loud for some drivers. Despite its higher sound output, the price remains similar to the Road version.

GReddy TIC

For those who want a deeper, more aggressive sound, the GReddy TIC is one of the best options available. Known for its bass-heavy rumble, the GReddy TIC offers a throaty exhaust note that’s not too overpowering but still lets your Miata’s presence be known.

The system is made from titanium, making it lightweight and durable. The thin titanium walls also produce a unique metallic rasp, adding even more character to your Miata’s sound. Priced at 330 pounds, the GReddy TIC provides a good balance between cost, performance, and weight reduction.

Goodwin Racing Raceback (Single Exit)

If you’re after a unique sound and some weight savings, the Goodwin Racing Raceback is worth a look. This single-exit exhaust produces a sharp, fruity tone that stands out compared to dual-exit setups. It’s also lighter due to the reduced piping, which can improve handling slightly.

The single-exit configuration offers a more free-flowing design, leading to marginal performance gains over dual-exit systems. While it’s priced on the higher side, it’s a great option for enthusiasts who want both performance and a unique exhaust note.

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