Mustang Cat-Back vs Axle-Back Exhaust Explained

Mustang Cat-Back vs Axle-Back Exhaust Explained

Last Updated October 15, 2020 | Chris Cervenka

Which Type Of Aftermarket Exhaust To Get For Your Mustang

Exhaust modifications can turn your V8’s engine growl into a roar. It’s no surprise that they’re one of the most popular modifications for Mustang owners. Since 2015, the Mustang has been sold globally, and Ford constructs their exhaust systems with that in mind. Though the United States also has regulations on exhaust noise, there’s certainly a lot of room to improve the exhaust note of your Mustang while still being considerate to your neighbors.

There’s little doubt that the factory exhaust is too quiet. That’s where aftermarket exhaust systems from trusted brands like Ford Performance, Magnaflow, Roush, Borla can help you love your exhaust note.

There are a lot of exhaust system components that you can change out to improve your exhaust sound. There are great headers for Mustangs, but one of the big choices you’ll want to make is what type of exhaust system is going to suit your build. For those looking to solely improve their exhaust note, an axle-back system should suit their needs, while Mustang drivers who are also looking for performance gains in addition to an improved sound should consider a cat-back system.

If you have an active valve exhaust system, you can also improve your exhaust note with an aftermarket system, but you do need to make sure that your aftermarket system is compatible with active exhaust.

What Are Axle-Back Exhaust Systems?

The name “axle-back” comes from the fact that this system replaces your exhaust from the rear axle to your exhaust tips. Of the two options, Axle-Back Exhaust Systems are going to hurt your wallet the least.

For 2005-2014 Mustangs, upgrading your axle-backs is a simple process that requires zero cutting and simply clamps in place of your factory mufflers. On the other hand, for 2015+ Mustangs, upgrading your axle-backs will require you to measure, cut, and clamp your new mufflers into place.

Borla S-Type Axle-Back Exhaust on a 2015-2017 Mustang GT

Essentially, adding an axle-back system to your Mustang retains everything that comes before the mufflers, which includes the factory exhaust manifolds, catalytic converter(s), midpipe, and intermediate pipe(s).

2005-2014 Mustang Owners: Unlike 2015+ owners, an axle-back swap is a relatively easy task for you. Once the car is up on ramps or on the lift, simply loosen the clamp connecting the muffler to the intermediate pipe and slide it off the hanger. Then, simply slide the new muffler on and tighten the clamp. Repeat on the other side and you’re finished!

2015+ Mustang Owners: Installing an axle-back is a bit more of a laborious task for S550 owners. Due to the one-piece design of the entire cat-back exhaust system on this new platform, the installation of an axle-back system, while retaining the factory resonator, will require cutting in order to remove the factory mufflers. Once you measure twice and cut once, simply slide the new mufflers into place and clamp them down. Adjust tips as necessary.

Obviously, there isn’t as much of a performance benefit when comparing an axle-back system to a cat-back, but for those who just want a more aggressive exhaust note without breaking the bank, an axle-back exhaust system is the way to go!

What Are Cat-Back Exhaust Systems?

"cat-back exhaust will allow better flow"

The “cat-back” exhaust system is defined just as it sounds; it’s an upgrade of the exhaust system from the catalytic converter(s) back. Meaning that the factory exhaust manifolds and catalytic converter(s) are retained, but the mid pipe, intermediate pipe(s) and mufflers are replaced.

Borla S-Type Cat-Back Exhaust on a 2015-2017 Mustang GT

Cat-back exhausts are more expensive than axle-backs, which makes sense given the additional complexity and importance of the replaced parts. The cat-back exhaust allows for better flow, considering most aftermarket cat-backs will replace the heavy, power-robbing resonator(s) that Ford includes on your car from the factory. So, you don’t only get the benefit of a better exhaust note, but you also get measurable power gains as well, especially in the upper range of your Mustang’s power band.

With a cat-back, you also have the option to switch up your mid-pipe depending on which manufacturer you’re looking at. Most Mustangs come from the factory with an H-Pipe style mid-pipe, which provides a deeper, more muscle-car-like exhaust note. You can replace it with the same style mid-pipe on your cat-back, like a lot of MBRP’s options, for the same general exhaust tone. However, on late model Mustangs, many of the aftermarket exhaust systems provide you with the option of an X-Pipe style mid-pipe. This will give your car a more high-pitched, European-inspired exhaust note. A good example would be any of Corsa’s exhaust systems. You can read more about X-Pipes vs H-Pipes in our other tech article!

For both the 2005-2014 (S197) and 2015-2019(S550) body styles, a cat-back exhaust system installation is pretty easy. You simply slide off the factory system and replace it with your new cat-back – no cutting required!

S550 GT Owners - Make Your Own “Cat-Back” System To Save Some Bucks

If you’re a 2015+ Mustang GT owner and the price point of a cat-back exhaust system is just a bit too high – don’t worry – there is another option for you! Many have found that picking up an axle-back system and combining it with a Resonator Delete X or H-pipe is a more cost-effective option than picking up a full cat-back system. This combination will require you to keep a small portion of your factory intermediate pipes while cutting and clamping the resonator delete mid-pipe and axle-backs into place. However, once you’re done, you essentially have a complete cat-back system for a fraction of the price!

Some owners have even said that the factory axle-backs sound pretty good once the resonator delete is installed.

Newsletter Sign-Up

Mustang Cat-Back vs Axle-Back Exhaust Explained

An axle-back system is great for those who are looking for that throaty exhaust note, aren’t as concerned with power gains and would like a reduced price point. A cat-back on the other hand, is for those who may plan on doing headers in the future, want a customizable option with an X or H pipe and want full power benefits from an exhaust system. Now that you know the difference between an Axle-Back and Cat-Back, you have the knowledge at hand to make an educated decision about the direction of your Mustang build’s exhaust system! Check out the CJ Pony Parts website for all of your Mustang’s exhaust needs!