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Roush Quad Tip Passive Axle-Back Exhaust (15-17 GT Premium)

Item 388835
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      Product Information

      Features, Description, Reviews, Q&A, Specs & Installation


      • ROUSH Passive Axle-back Exhaust System
      • Aggressive, Raspy Exhaust Note
      • Unique Open-Chambered Muffler Design
      • 304 Stainless Steel Construction
      • Full Mandrel-Bent Tubing
      • 4" Stainless Steel Quad Tips w/ Chrome Flashing
      • Fits 2015-2017 Premium Package GT Mustangs equipped w/ Roush Rear Valance


      Aggressive Raspy Sound. Let everyone know your 2015-2017 Premium Package GT has arrived with the aggressive, raspy sound of this Roush Quad Tip Passive Axle-Back Exhaust. This innovative Roush Exhaust system features a hollow, open chamber muffler that results in increased air flow and a unique sound, with no in-cabin "boom" normally found with performance exhaust at cruising speeds.

      Quality Roush Construction. Constructed from fully mandrel-bent 304 stainless steel for a durability, corrosion resistance and long life, the Roush Axle-Back Exhaust features two unique open chambered mufflers with 304 stainless steel dual wall quad tips. The 4" quad tips are finished with a new chrome flashing process that is resistant to discoloration due to exhaust heat.

      Passive System. Featuring block off plates for the two inner exhaust tips, this Roush Quad Tip Passive Axle-Back gives you the ability to cruise with just the two outer tips open or all four tips. Simply remove the inner plates to further improve the sound and performance of this Quad Tip Exhaust.

      Active Ready Kit. This passive exhaust system is also designed as an "Active Ready" Kit, which will allow you the option to easily remove the included block off plates and simply bolt-on Roush's Active Exhaust Module (sold separately).

      Cut & Clamp Installation. The installation of this Axle-Back Exhaust requires cutting, removing the factory muffler assemblies and clamping the new muffler assemblies in place. Clamps, hardware and installation instructions are provided.

      Application. This Roush Quad Tip Passive Axle-Back Exhaust System is designed to fit fastback or convertible 2015-2017 GT Mustangs equipped with the Premium Package and the required 2015-2017 Roush Rear Valance installed (valance sold separately).

      Fitment: 2015 2016 2017 Details

      Roush 421921

      CA Residents: WARNING: Cancer and Reproductive Harm -


      Customer Reviews (9)

      Write a Review

      Ratings Summary

      4.0 out of 5 overall rating from 9 customers

      Installation Time: Weekend

      Installation Cost: $100-$250

      • January 21, 2018

        3 2017 GT - JasonT Installation Time: Shop Install Installation Cost: $100-$250


        It has a nice sound but isn’t loud like I thought it would be from other reviews. It’s not worth the price at all. Only had it on for a month and it’s already has rust spots, so I doubt it’s 304. There are better sounding cat-backs that are less expensive. Get the Borla or Flowmaster

        Helpful (7)
      • June 27, 2017

        5 2017 GT - MustangQueen Installation Time: Shop Install Installation Cost: $100-$250

        Best Exhaust Ever!!

        I bought these for my 2017 Mustang and it sounds amazing once you take the bevel off. I later replaced the resonator with straight pipes and..... well let's just say my neighbors probably hate me :D However, I know it's a Roush quad tip exhaust system but it could have been just a bit cheaper since it's just an axel back. However, i love the sound so the price although a bit too high when you include the rear valence was totally worth it in my opinion. Every time I am driving the car I can't wipe that smile that just appears on my face. starting up is what I look forward to at 6 am on a Monday.

        Helpful (8)
      • March 01, 2017

        3 2015 GT - MustangforLife Installation Time: Shop Install Installation Cost: $250-$500

        Not for the Timid

        Under BANG for YOUR BUCK.. I was floored when I saw the Price..?? It jumped almost $150.00 from $994.00 to $1,124.99....

        Helpful (7)
      • January 27, 2017

        2 2017 GT - keystang Installation Time: Shop Install Installation Cost: 0-$100

        2017 Stang

        Love the idea of quad tips, more research and design, should have went into how rear valance would change the look of car.

        Helpful (7)
      • January 19, 2017

        5 2016 GT - Gatorman27 Installation Time: Afternoon

        Nice Quad Tips

        I spend over a year reviewing various muffler options for my 2016 GT C/S and finally decided on the Roush Quad Tip axle-back mufflers. I installed the Roush rear valance a week earlier than the muffler install so I was all set for the new mufflers. I decided on the Roush quad tips (passive exhaust) because of the block off plate option which gives me flexibility with the sound. And, I was very happy with this option right from the start. The installation went well but the instructions could have been a littler clearer regarding removing the existing mufflers (Roush provides two different measurements for cutting but the diagram wasn’t clear). Overall, the mufflers look and sound great!!! I recommend this product to anyone who is interested in an axle-backs with options.

        Helpful (11)
      • December 07, 2016

        5 2017 GT - S550


        If what you're looking is a super AGGRESSIVE and LOUD sound out of your 5.0 this is the way to go! is like a thunderstorm every time you step on the gas pedal!

        Helpful (7)
      • November 28, 2016

        5 2015 GT - FiveOhSlow Installation Time: Afternoon

        Awesome, but PAI installation

        First off, this exhaust screams 'murica and is not for those looking to be quiet or subtle rolling down the streets. There is no drone in this setup at cruising speeds even with a resonator delete H or X pipe, but getting on it you will not be disappointed. Now the installation for these was a pain in the a**. Make sure you check out Roush Performance's website and read the instructions carefully front to back. Even after you finish modifying your rear valance this setup still requires modification to the support frame of the car that will hold a new bracket for the exhaust hangers (each side has 2 instead of 1). I would recommend taking to a professional or having an authorized Roush Performance Ford Dealer work on it for you unless you are confident in modifying everything.

        Helpful (9)
      • June 15, 2016

        5 2016 GT - Wolverine92 Installation Time: Shop Install Installation Cost: $100-$250


        The Roush Quad Exhaust is totally what i wanted my car to sound like. With a custom x-pipe that i had done it has a nice tone to it at moderate speeds. When you go full throttle sounds even better it will have a nice raspy tone, on the highway in lower rpms its nice and quiet, no drone whatsoever. If you want everyone to hear you coming then i really recommend this exhausts! Your GT will sound like no other.

        Helpful (9)
      • December 25, 2015

        3 2015 GT - Adrian Installation Time: Afternoon Installation Cost: $100-$250

        Loud and Raspy

        I have a 2015 Mustang GT and installed this in addition to the rear valance. The exhaust itself is quite loud especially paired with the Ford Racing X-Pipe (Resonator Delete). Its incredibly raspy at high RPM's to the point where the note is just completely drowned out. Has a nice rumble at lower RPM's though. This is my third Mustang GT and I have experimented with quite a few setups over the years; stay away from this one if you do not want a deafening rasp to your exhaust note. As far as the appearance and fitment, it is decent - but requires cutting into the fender when installing this exhaust with the Roush rear valance.

        Helpful (9)

      Questions & Answers (11 answers)

      5 Top Rated Questions

      Will this fix the ARQ carbon fiber rear valence??

      • The Roush Quad Tip Passive Axle-Back Exhaust will fit with the Anderson Composites Type-ARQ Rear Valance - Carbon Fiber.

      Helpful (1)

      Is there a sound clip of this axle back?

      • We do not currently have a sound clip of this Roush Quad Tip Passive Axle-Back Exhaust, we apologize. We are working to have a sound clip and will have it loaded on this page as soon as it becomes available.

      Helpful (1)

      I know this is a "Roush" product , however I have the gt350 Rear Valance. I know they may have to be modifiers slightly but can these tips fit in the gt350 Valance ?

      • You are correct. You will have little to nothing to worry about with the GT350 valance.

      Helpful (1)

      Can I get this with flat black tips? If not, could I get these powder coated?

      • The Roush Quad Tip Passive Axle-Back Exhaust is only available with chrome tips at this time.

      Helpful (0)

      will this fit a 2014 ford mustang??

      • The Roush Quad Tip Passive Axle-Back Exhaust will not fit the 2014 Mustang. his Roush Quad Tip Passive Axle-Back Exhaust System is designed to fit fastback or convertible 2015-2017 GT Mustangs equipped with the Premium Package and the required 2015-2017 Roush Rear Valance installed (valance sold separately).

      Helpful (0)
      Post Your Question
      6 More Questions
      I have the Roush Axlebacks(single tips) do these sound any different from those. 1 answer
      Will these fit on my 2015 mustange gt without any modification 1 answer
      How much hp it gained after install this ? 1 answer
      I have the roush axle back and ford x pipe install if I were to purchase this would it affect anything? Or would I be required to do more cutting as to installing the axle backs and would it affect the x pipe? 1 answer
      Is the Active Exhaust Upgrade required? If not, would I be able to install the Active Exhaust Upgrade after I install the actual Exhaust? 1 answer
      Does it fit with 2016 GT350 rear valance? 1 answer

      Installation & What's in the Box

      Installation Info

      What's in the Box

      • (2) Axle-Back Assemblies
      • (2) Quad Tips
      • (2) Block Off Plates
      • (2) Block Off Plate Gaskets
      • (6) Clamps
      • Installation Hardware

      Tech Specs

      Cat-Back Exhaust Specifications
      Piping Material:304 Stainless Steel Tip Material :304 Stainless Steel with Chrome Flashing
      Piping Size:2.5"Tip Size:4"
      Muffler Type:Open ChamberedFitment:2015-2017 GT

      Will It Fit My Mustang

      • GT - 15, 16, 17

      Compatible with Premium Package GT Mustangs equipped with required 15-17 Roush Rear Valance only

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