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

Market Price $2,689.99 You Save 1% ($30.00)
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  • Item 389790
  • MPN# 421924

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    Features & Details

    • ROUSH Active Axle-back Exhaust System
    • Select Between Touring, Sport, Track and Custom Exhaust Notes
    • Custom Programming with Included WiFi OBD2 Interface and Roush iOS App
    • Unique Open-Chambered Muffler Design
    • 304 Stainless Steel Construction
    • Full Mandrel-Bent Tubing
    • 4" Stainless Steel Quad Tips With Chrome Flashing
    • Cut & Clamp Installation
    • Fits 2015-2017 Premium Package GT Mustangs equipped with a Roush Rear Valance
    ROUSH Active Exhaust System. Take total control of the volume and performance of your S550 GT Mustang with a ROUSH Active Exhaust system. Roush's proprietary Active Exhaust system ties directly into your Mustang's powertrain control module, opening and closing the mufflers valving based on throttle position.

    Four Distinct Exhaust Sounds. The ROUSH Active Exhaust System includes a center console mounted selector knob that allows you to easily switch between four different sound modes on the fly. Choose from Touring, Sport, Track, and Custom.
    • Touring. The Touring mode closes the mufflers valves completely keeping the exhaust volume to an absolute minimum.
    • Sport. The Sport mode keeps the exhaust quiet during normal driving conditions. Accelerator position and vehicle speed are used to determine valve position, opening up under acceleration for a more aggressive sounding ride.
    • Track. The Track mode is wide-open. This mode keeps the exhaust tailpipe valves fully open at all times and doesn't restrict the raw sound of your Mustang. This mode is intended for track use and is not legal for street use.
    • Custom. The Custom mode lets you create a custom sound map with the included WiFi OBD2 interface and ROUSH iOS application to personalize the exhaust sound to your own tastes. With the app you gain full control over the position of the valves based on vehicle speed, rpm and accelerator position. Download the free ROUSH Active Exhaust App for iOS - Here

    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.

    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 Active Axle-Back Exhaust System is designed to fit fastback or convertible 2015-2017 GT Mustangs equipped with the factory Premium Chassis Package (Trim Levels: 400A/401A) and will require the use of the Roush Rear Valance 421894 or 421919 for proper installation (valance sold separately).

    Download the Roush active exhaust app instructions - Here

    Fitment: 2015 2016 2017 Details

    What's in the Box
    • (1) Exhaust Pipe with Valve – LH
    • (1) Exhaust Pipe with Valve – RH
    • (1) Flashed Controller, Active Exhaust
    • (1) Vehicle Ready Wiring Harness 
    • (1) OBDII Active Exhaust Programmer
    • (1) Hardware Kit – Active Exhaust
    • (1) Switch, Mode Selector
    • (1) Switch Plate, Metal with Engraving
    • (1) Switch Bracket
    • (2) Bolt – M4 x 0.7 x 10
    • (2) Push Nut – 3/16” 
    • (3) Washer – M4 Nylon 
    • (7) Zip Tie with Edge Clip
    • (1) Knob, Knurled Style
    • (1) Set Screw – M3 x 0.5 x 6 
    • (1) J-Clip – M6  
    • (1) Bolt – M6 x 31 HEX
    • (2) Foam Tape 30 mm x 35 mm x 7.9 mm
    • (1) Micro Fuse – 10 AMP   
    • (20) Zip Tie – 7”  
    • (1) Multipurpose O-Ring, 5.6 mm
    Installation Info
    Tech Specs
    Will it fit my Mustang?

    Customer Photos (1) Submit Your Photo

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    12 Questions / 7 Answers

    Ask a Question

    Will this kit fit in the gt350 rear valance, or be adaptable to fit onto the gt350's quad tip kit for the normal GT premiums? that valance looks night and day better and would give people more options.


    • From the given image of this product by American Muscle and Roush Performance websites, I will say this muffler definitely will fit the GT350 rear valance since the sizes seemed to fit. I have a complete FRPP GT350 Sport exhaust kit. GT350 valance has the end tips mounted on the valance and i deem that the roush muffler will fit if the roush end tips is not installed. Actually I am waiting on the shipment of this Roush exhaust and I will try then I can give this question a more reliable answer.


    Show 1 more answer Helpful (2)

    Will you need a tune after installation?


    • No the Roush Quad Tip Active Axle-Back Exhaust will not require a tune after installation. It does include the ability to adjust the exhaust valves in order to create a custom exhaust tone, however this is easily done via the included OBD2 interface and Roush Active Exhaust app for IOS.


    Helpful (0)

    Is this exhaust 2.5 in or 3 in?


    • The Roush Quad Tip Active Axle-Back Exhaust features stainless steel 3" piping.


    Helpful (0)

    Can you put this on a base 2016 gt


    • Unfortunately the Roush Quad Tip Active Axle-Back Exhaust will not work with a base model GT as it is designed to fit a 15-17 GT Premium model with the Roush Rear Valance installed (For vehicles with back-up sensors: For vehicles w/o the back-up sensors:


    Helpful (0)

    What diameter is this axle back I’m running longtubes to a 3” kooks catback


    • This Roush exhaust's connections will indeed be 3 inches in diameter.


    Helpful (0)

    Will this fit a mustang GT Premium Convertible?


    • Yes, this Roush Quad Tip Active Axle-Back Exhaust will fit a convertible GT Premium. Just be sure to choose the "Convertible" option, which brings up item number 389790-B.


    Helpful (0)

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    Customer Reviews (6) Write a Review

    Overall Rating 4.2

    out of 5 stars

    Installation Time:Weekend

    Installation Cost:$500-$1000

    • Loudness / Volume 4.8 4.8
    • Exhaust Note 5 5
    • Fit & Finish 4.4 4.4
    • Bang For Your Buck 4.2 4.2

    • 3/5

      Installation Time: Shop Install

      Installation Cost: $500-$1000

      November 21, 2017

      Awesome when it works.

      We had the exhaust dealer installed on our 2016 convertible gt. It was awesome for about 3 months then faulted our and would stick with one side open and one closed or both closed.. there is no rhyme or reason. I can have both open in track mode cruising at 70 on the interstate and it just faults. Light comes on I check it out and one side will be closed. Sometimes you can shut the car down and start it back up and it will correct itself, only to later fault again. I will say that roush has been all over getting my parts for repair.. i have had the car since July of 16 and am on my 3rd set of butterfly valves. They have a 3 yr warranty on the entire system except the switch. All in all it looks great and sounds great. I am told the kinks have been worked out.


      Year: 2016 Submodel: GT

      Helpful (2)

    • 5/5

      Installation Time: Afternoon

      October 07, 2017

      LOVE IT!!!!!

      I ordered this for my 16 convertible GT and a Roush X pipe. Everywhere I go people give me thumbs up and want to talk about my exhaust. I love the ability to flip the switch, although I ride around in track mode all the time. You get what you pay for! Roush does not disappoint!!! If you’re looking for a loud, low grumble, this is the way to go!


      Year: 2016 Submodel: GT

      Helpful (1)

    • 5/5

      Installation Time: Weekend

      July 24, 2017


      YouTube videos don't do this exhaust justice. Roush says it takes 9 hours worth of labor and that's pretty accurate. Ford took 12 hours to install this system along with the Roush C pipe (which I recommend doing all at once). It's definitely the most expensive system for the S550 but you definitely get the best bang for your buck. Being able to turn down your exhaust when it's late at night near your house or when you see a cop sitting at the light has already been worth it.


      Year: 2015 Submodel: GT

      Helpful (1)

    • 3/5

      June 06, 2017

      Sounds Great but Flawed

      I have an Active Exhaust system on my 2015 Roush Stage 3 and I have mixed feelings. When it works, it sounds great, but over the past 18 months it has been into the dealer for repair work 3 times, and still fails (it's in again now). It will work for a while, then just fails (and when it fails, it fails to the quietest setting, which isn't really the point!). Also, there is NO Android support for the app to control custom mode, and, per Roush, there is absolutely no plan to ever add Android support, so if you want to play with the custom settings, and use Android, think twice...


      Year: 2015 Submodel: GT

      Helpful (5)

    • 4/5

      August 30, 2016

      Make sure to order the correct one!!!

      Awesome product. Looks great, sounds even better! One important thing to note when you order, if also ordering the matching Rear Valance: It will ask you to choose from: "Rear Valance with sensor holes" or "Rear Valance w/o sensor holes" I wasn't sure, so I went and took a look, and while I did notice I have back up sensors, they were not located in the rear valance, (actually located in the bumber several inches above it). Assuming Ford made other models that had the back up sensors located IN the valance...I indicated "Rear Valance w/o sensor holes" so I would not have 4 holes in my new valance unused. So after dismantling the back end of my car, and having already cut up my bumper to fit the new valance(yes you will need to do that to install this)...I then discovered that the new valance is taller than the old, and installs OVER the back up sensors on the actual bumper. Noooow I understand... ;-) Being my only vehicle, needing to get to work the next day, and with my old one not able to go back on due to all the cutting...I had no choice but to install it over the sensors. The backup sensors now toss up an error message on my screen every time I back up, and of course not functioning. With that said I absolutely love the product itself. It just stinks that having already bought it once, now I have no choice but to save up another $250 bucks to order the correct one, and spend another half day making the swap. So please take heed! If you have backup sensors, (even if they are not located in your existing rear valance) get the one with the holes for them, as it will cover them up!!! Note to AM: A loyal customer for years now modding two mustangs, and have nothing but great things to say about AM, you guys rock! But please do others a favor and make a note about the back-up sensors on the product page...that it WILL cover the existing even if NOT located in the existing valance but above it! My bad for overthinking I guess, and I'm sure some others maybe laughing over this post :-), but would hate to see someone else make the same mistake! Once my piggy bank is full again...I'll be placing my order for the correct one. Until then "ERROR: BackUp sensor FAIL"...but will sound good while I clear it each time ;-)


      Year: 2015 Submodel: GT

      Helpful (11)

    • 5/5

      April 13, 2016

      Great Value and Overall Great Quality

      Great product, worth the price and then some. Sounds amazing!


      Year: 2014 Submodel: GT

      Helpful (2)

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