The Differences Between Axle-Back And Cat-Back Exhaust
Last Updated: October 15, 2021
We all know that with the Mustang, half of the appeal is the sound the car makes. It plays a major part in the driving experience of the car and whether it is subtle but smooth-sounding or loud enough to hear from blocks away, the exhaust in a muscle car is one of the most important factors for any enthusiast. Hearing the rumble of the engine in addition to feeling the power under your feet is all part of the thrill of driving something like a Mustang regardless of the engine. This experience is what makes the Mustang so enjoyable, and why the exhaust market for them is so abundant with different brands, parts, and setups.
Now, when it comes time to upgrade your Mustang’s factory exhaust to something with a bit more power and sound behind it you are faced with a much larger decision to make than you may think. When deciding which exhaust to run, you need to compare and contrast the benefits and negatives of each style and brand to ensure you get the right sound for you. Outside of different headers styles, there are two main styles of exhaust you can install - axle-back or cat-back - and each has its pros and cons depending on the setup and what is expected of the brands. So when it comes time to decide what you want to use, it is important to consider each part before purchasing.
Axle-Back Exhaust: Basics
When considering an axle-back exhaust, you will need to think of a few things in reference to it. An axle-back will cost you less upfront because obviously it is less material used to develop them and take less time to install. These exhausts tend to range in any price from a few hundred to generally around $800 depending on which generation Mustang it is for. With S197 axle-back exhaust for example, the price range is from just under $330 going to $1,840 for the top-of-the-line exhaust setups with resonator delete pipes as well.
Axle-back exhaust is a great option for someone new to modifying their Mustang for sound. They can easily bring out a seriously aggressive exhaust note while helping improve backpressure and even horsepower. While these gains may be fun, they are still limited in their capabilities. An axle-back exhaust may not be able to provide as much power as other setups like cat-back exhausts. What an axle-back provides in ease of install and price is where it does generally fall short compared to more expensive options.
Cat-Back Exhaust: Basics
If you want to have a seriously high-performance exhaust system for your Mustang, a cat-back is one of the top choices. Cat-back exhausts run from the secondary catalytic converters to the end of the car, generally eliminating resonators and modifying the mufflers as well in addition to changing the pressure in the piping behind the catalytic converters. Cat-back exhausts are more pricey than axle-back exhausts since they take more work to install and use more material to perform properly, but the benefits from these exhausts outweighs their price point generally. For a cat-back on an S550 for example, you can expect to pay from $425 to over $3,100 for some systems.
While the price may be high, so is the performance increase. While many axle-back exhausts will be able to increase horsepower by up to 30 horsepower while a properly set up cat-back can provide more in ideal conditions. Cat-back exhausts provide a more aggressive exhaust note than axle-back systems because they are less restrictive than the axle-back which still uses the majority of the factory exhaust system. The cat-back exhaust may be more expensive upfront, but provides a good platform of investment moving forward while an axle-back may be fitted with various other parts like resonator delete pipes and high-flow catalytic converters to develop a complete exhaust system.
Axle-Back vs Cat-Back: Appearance
From a design standpoint, the back half of these exhausts are similar. Since the cat-back includes its own axle-back system in its design, the appearance of the two can sometimes look shockingly similar. A cat-back is generally more intricate or detailed, however, since there is more piping that must be used throughout the exhaust system. With more straight-through piping, the sound of the exhaust in a cat-back has more time to reverberate and build volume which in many cases is what many people do on their high-performance vehicles to make them as loud as they are.
With axle-back exhaust, the appearance from underneath the car is more obvious when paired with stock exhaust, especially if it has been used for a long time already. While the appearance will change quickly as the car is driven more frequently, there will remain a distinct new look that only extends to the resonators. The axle-back as compared to the cat-back looks slightly unfinished at first because of only the rear section of the exhaust being modified but will perform exactly as intended.
Axle-Back vs Cat-Back Exhaust: Experience
Axle-back exhaust systems are a great way to make your car louder and perform better than it would when it left the factory floor. With some axle-back exhausts being noticeable loud, such as systems from MBRP, Steeda, Roush, and Corsa Performance, it is easy to see why people might choose a simple setup like these. These are an easy way to give your Mustang more personality and completely change their exhaust tone and volume for much less money than most cat-back systems. Lightweight and durable, an axle-back is a simple exhaust upgrade that can make a massive difference in your Mustang’s road presence regardless of which motor your Mustang runs.
Cat-back exhausts cater more towards the higher end of the upgrade market because of their price and their quality. A high-quality cat-back is able to eliminate any drone as well as giving your car a louder and more full exhaust tone under heavy acceleration as well as at idle. A cat-back exhaust such as the AWE Mustang GT Touring Edition Cat-back offers volume and quality without droning while cruising at any speed. While it can do this, the exhaust comes into its own when under heavy throttle before leveling out back to normal. Generally lightweight and with major performance benefits, a cat-back exhaust can be the perfect addition to your Mustang’s exhaust system.