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Flowmaster Outlaw Axle-Back Exhaust (15-20 EcoBoost w/o Active Exhaust)

Item 525581A
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Market Price $484.71 You Save 12% ($55.76)
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      Review & Installation Video

      Product Information

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


      • Super Aggressive Flowmaster Outlaw Sound
      • Durable 409 Stainless Steel Construction
      • 2.5" Mandrel-Bent Tubing
      • 4" Polished Stainless Steel Tips
      • Includes Two Flowmaster Outlaw Mufflers
      • Not Compatible with Active Exhaust
      • Fits 2015-2020 EcoBoost Mustangs


      Super Aggressive Flowmaster Sound. Give your EcoBoost powered Mustang that unmistakable Flowmaster sound with the Outlaw Series Axle-Back exhaust system from AmericanMuscle. This system improves exhaust flow using Flowmaster's race-oriented style Outlaw mufflers for that super, aggressive exhaust note your high powered Pony deserves.

      Stainless Steel Construction. Constructed from durable 2.5" 16 gauge 409 stainless steel tubing for it's corrosion resistant properties, the Flowmaster Outlaw Axle-Back features (2) race-oriented mufflers with massive 4.0" diameter polished stainless steel tips for impressive muscle car looks and sound. As an added bonus, the tips are embossed with the "Flowmaster" logo for true custom styling.

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

      Application. This Flowmaster Outlaw Series Axle-Back exhaust system is designed to fit the 2015-2020 EcoBoost Mustangs without the Active Valve Exhaust.

      Fitment: 2015 2016 2017 2018 2019 2020

      MPN# 817713

      CA Residents: WARNING: Cancer and Reproductive Harm -


      Customer Reviews (100+)

      Write a Review

      Ratings Summary

      4.8 out of 5 overall rating from 100+ customers

      Installation Time: Afternoon

      Installation Cost: $100-$250

      • April 06, 2020

        4 2017 EcoBoost - Kendrick


        yep loves these pipes but sometimes i wish i had a v8

        Helpful (0)
      • April 05, 2020

        Review shared from Flowmaster Outlaw Axle-Back Exhaust (15-17 V6)

        5 2017 V6 - Adee Installation Time: Shop Install Installation Cost: 0-$100

        Gr8 mod

        First mod on my car Love driving with that super sound. Awesum

        Helpful (0)
      • April 04, 2020

        5 2019 EcoBoost - Gagyuuq Installation Time: Less than 1 Hour

        Great sound

        Good quality sound, not loud but not soft. Just perfect

        Helpful (0)
      • March 31, 2020

        Review shared from Flowmaster Outlaw Axle-Back Exhaust (15-17 V6)

        5 2016 V6 - mdrngreaser Installation Time: Less than 1 Hour

        Awesome value

        Awesome value for what you get, super easy to install and great sound for one of the cheaper available kits. Really brought my v6 to life. No drone in the car either once you get to cruising speed.

        Helpful (0)
      • March 30, 2020

        5 2017 EcoBoost - KennyD

        A nice roar for a Eco

        This made my 2017 Ecoboost sound pretty darn aggressive, I love it. Not too loud but also not too quiet!

        Helpful (0)
      • March 02, 2020

        5 2015 EcoBoost - maddieh Installation Time: Less than 1 Hour

        sounds great!!

        was a little hesitant purchasing in the beginning just because i looked up videos of this exhaust and i wasn’t too thrilled with how it sounded.. but after i got it installed it sounds great and i’m super happy with it!! on a cold start you can really tell a difference. highly recommend!

        Helpful (1)
      • January 27, 2020

        Review shared from Flowmaster Outlaw Axle-Back Exhaust (15-17 V6)

        4 2017 V6 - MyrtleBeachLife Installation Time: Shop Install


        Sounds great on cold start. Quiet when your not on the gas. Sounds good at low rpm and higher rpms. Around 2k rpms sounds like a honda at least from inside the car. Drone is extreme in that 2k range as well. Hopefully H pipe will help.

        Helpful (2)
      • January 21, 2020

        5 2017 EcoBoost - DominicM Installation Time: Less than 1 Hour

        Awesome exhaust system

        It is a good sounding exhaust for EcoBoost. The sound is awesome doesn’t sound like a lawnmower and looks super aggressive. Pretty easy install as well.

        Helpful (0)
      • January 10, 2020

        Review shared from Flowmaster Outlaw Axle-Back Exhaust (15-17 V6)

        5 2005 V6 - Reezy Installation Time: Shop Install Installation Cost: 0-$100

        Amazing Exhaust Sound

        The Outlaws are undefeated!!! The exhaust is very aggressive and has a nice rumble at idle. It is not raspy at all. If you like drone then these are for you because it's plenty of it.

        Helpful (0)
      • November 26, 2019

        Review shared from Flowmaster Outlaw Axle-Back Exhaust (15-17 V6)

        4 2015 V6 - BrandonD Installation Time: Afternoon

        A little loud

        Love the sound but is a little louder than I originally expected.

        Helpful (1)

      Questions & Answers (58 answers)

      5 Top Rated Questions

      Does installing the Flowmaster Outlaw Series Axle-Back Exhaust on my 2017 Mustang eccoboost affect the new vehicle warranty from FORD?

      • Hello, Ford explained to me that the only way and after market part would void the warranty is it poorly malfunctioning.

      Helpful (15)

      I have the convertible version of the 2015 Mustang Ecoboost Premium. With this axle-back fit?

      • The Flowmaster Outlaw Series Axle-Back Exhaust is designed to fit both coupe and convertible ecoboost Mustangs.

      Helpful (9)

      is this product legal in the Rio Grande Valley ,Texas

      • Unfortunately, we are not familiar with the local laws and regulations in your city. Please contact your local Department of Transportation, and/or Law Enforcement Agency.

      Helpful (4)

      I live in California. If i put this on, will i still pass smog? This is probably the only reason holding me back. I have a 2017 v6 mustang.

      • The Flowmaster axle backs will pass smog testing however you will want to check your local laws on noise restraints to be safe.

      Helpful (4)

      Is this system compatible with the Flowmaster Scavenger series Y-pipe?

      • The Flowmaster Scavenger Series Cut and Clamp Resonator Delete Y-Pipe, Item 389694 is compatible with these axle-backs.

      Helpful (4)
      10 More Questions
      Everything comes as shown in the photo? 1 answer
      Does it require a computer tune? 1 answer
      Is it absolutely necessary to cut and bolt on or can I get away with not cutting at all? 1 answer
      I live in California and was wondering if this exhaust system is CARB certified. Would it pass smog check if I install it on my car? 1 answer
      Would this fit my 2019 EcoBoost Mustang? 1 answer
      I want to get a resonator delete and I was wondering if this would fit on with a MRT y pipe resonator delete? 0 answer
      Will the sound be above 95dB if put on 2019 Ecoboost Mustang? Is there any drone inside at 2000 RPM? 1 answer
      Will this pass emissions inspection in Virginia? 1 answer
      I installed this and for some reason my car throttle seemed slower why is that ???? 1 answer
      I saw in a previous response that this is CARB legal and was wondering if I could get a CARB sticker 1 answer

      Installation & What's in the Box

      Installation Info

      What's in the Box

      • (2) Muffler Assemblies

      Tech Specs

      Axle-Back Exhaust Specifications
      Piping Material:409 Stainless Steel Tip Material :Polished Stainless Steel
      Piping Size:2.5"Tip Size:4.0"
      Muffler Type:Straight-throughFitment:2015-2017 EcoBoost

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