How to Install a Roush Axle-Back Exhaust on a 2015-2017 Mustang

How to Install a Roush Axle-Back Exhaust on a 2015-2017 Mustang

Last Updated August 8, 2023 | Bill Tumas

Roush Axle-Back Installation For 2015-2017 GTs

The Roush Axle-Back was one of the more popular systems for the 2011-2014 Coyote Mustangs, especially if you keep the rest of your exhaust system stock. It offered a very aggressive tone when on the throttle, but at highway speeds, it was tame and offered no drone at all. When Roush Performance announced a similar system for the 2015 Mustang, we knew we had to get our hands on one. So, today we're going to show you how to install one on your 2015 GT.

Note: For those with S550 EcoBoost or V6 Mustangs, installation is virtually the same process.

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CJ Installation Video

Step-By-Step Instructions

Tools Required:

  • Lift or Jack and Jack Stands
  • 1/2” Ratchet
  • Low Torque 1/2” Impact Gun
  • 15mm Deep Socket
  • File
  • Marker
  • Safety Glasses

Installation Time: ~1 hour

Difficulty: Moderate

Tools laid out for installation

  1. The instructions provided by Roush tell you to cut the pipe closest to the tangent of the curve. The tangent is the closest straight line to the curve of the pipe. You want to follow the curve over and as soon as it gets to a straight section; that's roughly where you're going to cut. Do the same thing on both sides.

    Tech Tip: We recommend doing one side at a time in case you need to reference the other side during installation. Exhaust with line drawn to indicate where to cut
  2. To make sure you're in the right neighborhood, grab the Roush muffler. You're going to hold it up approximately where it's going to go. Then make sure this lines up with where you're going to cut. Holding up the Roush Muffler
  3. Once you see that everything lines up well, you can cut the pipe.

    Tech Tip: Since you'll need two hands to control the saw, if you don't have someone to hold the pipes for you, stuff some rags around the tip. That way, it doesn't bounce up against your valance. Pipe with rag stuffed around it cutting through the exhaust
  4. Now you can slide the muffler off the factory hanger. Then you'll want to de-burr it before we put the new pipe on. Filing down after cutting
  5. Now you’re ready to slide the new Roush Axle-Back Muffler into place. With the clamp slid into place on the muffler pipe, make sure it's a spot where you can reach in to tighten it. You’re now going to put it up into the hanger the opposite way you pulled the factory muffler out and slide muffler pipe over the factory intermediate pipe. Roush exhaust in location
  6. Grab the supplied tips that are fully adjustable in this case. Slide a clamp on, and make sure you get it where you want it. You can push it all the way down and bottom it out, but it typically looks a bit better if the tip is flush with the valence. Sliding the exhaust tip into place
  7. Once the tip and piping aligned correctly, go back and tighten both clamps down.

    Tech Tip: Roush recommends against using an air impact for this part of the job. Use a hand tool, or a cordless, battery-powered low torque impact gun like Bill’s. Using an impact gun to tighten the clamps
  8. Repeat the process on the other side and your installation is finished! A perfectly installed Roush exhaust

Some Notes On The Exhaust Note/Drone

Inside the car, the tone is very similar to the '11 through '14. It has that same kind of aggressive sound to it, but it's quieter. We actually don't think the exhaust is quieter, it's just that the 2015 is actually much quieter inside so we think it's deadening a lot of the sound out. When you're at highway speeds, you can't even hear it. No drone, no nothing at all. But, when you downshift and get on it, you’ll hear that nice aggressive sound we're all used to from Roush mufflers.

That Roush sound that was so popular with 2011-2014 Mustangs is alive and well for the '15 too. It sounds nice and aggressive when you get on it, but on the highway, it's very mild with no drone whatsoever. Installation is also pretty straightforward. Probably take you only around an hour.

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Please Note: Please keep in mind that this guide is a tool to help you install the parts on your vehicle. If you don’t feel confident in performing this installation properly on your own, have a professional install the parts for you.

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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.