Which Flowmaster Exhaust Is Right for You?

Which Flowmaster Exhaust Is Right for You?

Last Updated June 14, 2023 | Meghan Drummond

Flowmaster is one of the largest exhaust manufacturers in the aftermarket space. They're perhaps best known for their robust lineup of mufflers, each with a slightly different set of properties. You’ll also find these mufflers installed on their cat-back and axle-back exhausts.

The large offering is a strength, but it can leave people wondering which muffler is right for them.

Here’s a breakdown of Flowmaster’s most popular lines, including the loudest mufflers, the quietest ones, and everything in between. Click on each to learn more!


Outlaw Muffler on a dark red background

The Outlaw was originally designed as a race muffler. It’s very, very, very loud. By far the loudest of Flowmaster’s lineup.

Outlaw Muffler Sound

The Outlaw has a tubular design, like a glasspack. But while glasspacks use fiberglass to muffle sound, the Outlaw uses sound attenuation rings. This means there’s no blowout to worry about.

A lot of people see that this is the loudest muffler and jump straight to it. But its design is also focused solely on performance, which will cause some interior drone and resonance. That’s not a big deal if you’re actually using it for race applications, but it will get annoying if you’re driving it for longer periods of time.

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Super 10

Super 10 muffler on bright red background

The Super 10 is another very aggressive muffler. One of its advantages is that it’s very small and stout. With a single chamber, it can be compact and loud. This makes it great for installations where there may not be much space.

The Super 10 is designed to be a great fit for trucks as well as high-performance V8s that frequent the strip. Unlike the Outlaws, the Super 10 uses Delta Flow technology. Delta flow was specifically designed to cancel out some of the interior exhaust noise without sacrificing volume.

Gif shows how baffles used in delta flow eliminate drone
Delta Flow In Action

That said, the Super 10 is still going to create a lot of cabin noise.

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Super 44

Super 44 Muffler on orange-green background

Unlike the Super 10, the Super 44 has two internal chambers. This helps give it a deeper sound. Like the Super 10, you will still get a lot of interior noise.

There are a lot of people who say the 44 and 40 series are really close in terms of volume. According to Flowmaster, the 44 is designed to be louder and definitely has more rumble to it.

A lot of Super 44 owners have noticed exhaust drone. Especially when traveling at highway speeds.

Many of Flowmaster’s American Thunder exhaust systems have Super 44s installed. This system works really well, and buying all the parts together can help reduce the drone.

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40 Series

40 Series Muffler on a Yellow backdrop

The 40 series is one of Flowmaster’s most famed options. If you have a Fox Body with a 5.0, this is the perfect muffler for you. But this loud, aggressive muffler is a good fit for lots of muscle cars and trucks.

One of the reasons people love this muffler is because of its traditional muscle car sound. It’s still a very loud muffler though.

40 Series Muffler Sound

The two-chambered design is a good fit for performance builds. You’ll reduce backpressure and get the performance boost you want. These mufflers were designed to be heard from inside and outside your vehicle, so you’ll definitely get a lot of sound feedback from the driver’s seat.

Drivers add that they love the low, deep rumble at idle. At low RPMs, it produces an especially aggressive sound. Some people noticed exhaust drone at higher RPM. And above 2,400 RPM, conversation becomes difficult to impossible.

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Super 40

Super 40 muffler on a dark green background

If you love the sound of the 40s but hate exhaust drone, then the Super 40 might be a great fit for you. Unlike the single baffle design of the 40 series, the Super 40 uses the 3-baffled Delta Flow design. So, same great aggressive exhaust but without the drone.

Super 40 Sound

Naturally, the Super 40 is also a little quieter as well. A lot of people prefer this, because the quieter sound emphasizes the bass notes, creating a deeper rumble.

Some have described this as a “more adult” version of the 40. If you’re going to be doing more highway driving, these might be a better fit for you than the original 40 series.

The thicker case is part of how the Super 40 can support high-output applications without creating a huge amount of drone.

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Delta 40

A 40 series delta flow muffler on a green background

Considering the Super 40 uses Delta Flow, it’s a little confusing to name another muffler “Delta 40.” Basically, this muffler is the 40 series with the least interior resonance. If you love the 40 series but are opposed to any kind of drone, this is the right muffler for you.

This is also going to be the quietest out of the 40 series, but that’s when compared to some of the loudest and most aggressive mufflers. This will still blow your stock muffler away, and people will be able to hear your car coming.

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Flow FX Muffler on green-blue background

The FlowFX is a perfect muffler for drivers who care mostly about performance while still enjoying a great exhaust sound.

While most of Flowmaster’s lineup consists of chambered mufflers, the Flow FX is a straight-through design. Even though some FlowFX models look a little chunky to be straight-through, it’s because they include a lot of sound packing.

The result is the performance of a straight-through and a moderate exterior sound with little interior resonance. At cruising RPM, many drivers don’t really notice it.

So. Better performance. Great sound. Low drone. It’s kind of a perfect choice.

Unlike many mufflers, which are near-universal, you’ll need to get FlowFX mufflers that fit your model. And even then, you may want to measure depending on what other mods you’ve got.

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50 Series Delta Flow

A 50 series delta flow muffler on a blue background

The 50 Series Delta Flow offers a moderate muffler sound. Many have described it as throaty and natural. Unlike the more aggressive options, you’ll hear reduced exterior sound and less noise inside the cabin as well.

Even if you live in a well-populated area, you can safely install this muffler and stay on your neighbor’s good side. That said, the 50 Series Delta Flow will still be louder than stock and return some of your lost horsepower.

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Flowmaster’s lineup offers a lot of different sound profiles. Once you understand the naming setup, it’s a little easier to select the one that’s right for you. If you’re not partial to one specific brand, check out our other exhaust guides for even more selection.

Source: Muffler Tech: Corsa’s Reflective Sound Cancellation vs. Flowmaster’s Delta Flow Technology, On All Cylinders

This article was researched, written, edited, and reviewed following the steps outlined in our editorial process. Learn more about CJ's editorial standards and guidelines.