Mustang Cat-Back vs Axle-Back Exhaust Explained

Mustang Cat-Back vs Axle-Back Exhaust Explained

Last Updated November 17, 2016

Which Type Of Aftermarket Exhaust To Get For Your Mustang

One of the first mods that any Mustang owner looks to get for their stock car would be exhaust. There’s no question that Ford seems to really muffle the signature V8 growl down to a bare minimum from the factory. This is done for various reasons, two of which being efficiency and noise restrictions. This was even more of a focus for the 2015 Mustang due to the fact that Ford was going global with the S550 platform, where some countries are even more stringent on exhaust volume than the United States.

With that said, any enthusiast can agree that the factory exhaust is too quiet. And with driving one of the most iconic American V8 muscle cars, you want to be sure that you have the exhaust note to back up those eight cylinders of fury! That’s where aftermarket exhaust systems from trusted brands like Ford Performance, Magnaflow, Roush, Borla and many more come in!

Most new Mustang owners aren’t looking to mess with the exhaust manifolds or headers off the bat, so this article will focus primarily on cat-back and axle-back exhaust systems. Be sure to check out our other tech article on Long Tube and Shorty Headers to learn all about exhaust header options for your Mustang.

Axle-Back Exhaust Systems

"cat-back exhaust will allow better flow"

Of the two options, Axle-Back Exhaust Systems are going to hurt your wallet the least. The name “axle-back” comes from the fact that this system replaces your exhaust from the rear axle to the tips out your rear bumper cover. For most, axle-back exhaust is a modification simply for exhaust note. If you’re looking for both sound and performance gains, then a cat-back system may be the choice for you.

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.

Essentially, adding an axle-back system to your Mustang retains everything forward of 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!

2015-2017 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!

Cat-Back Exhaust Systems

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

For both the 2005-2014 (S197) and 2015-2016 (S550) body styles, a cat-back exhaust system installation is pretty easy. You simply can slide off the factory system and replace it with your new cat-back – no cutting required!

We’re sure you’re wondering why someone should pick a cat-back exhaust over an axle-back – especially with a higher price point on the cat-back. Well, the cat-back exhaust will allow 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 too; 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!

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

If you’re a 2015-2017 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.

Mustang Cat-Back vs Axle-Back Exhaust

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!

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