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Flowmaster Outlaw Cat-Back Exhaust (15-17 GT Fastback)

Market Price $1,110.99 You Save 12% ($128.61)
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$982.38

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  • Item 387145
  • MPN# 817734

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    Features, Video & Details

    • Super Aggressive Flowmaster Outlaw Sound
    • Durable 409 Stainless Steel Construction
    • 3" Mandrel-Bent Tubing
    • 4" Polished Stainless Steel Tips
    • Includes X-Pipe and Two Flowmaster Outlaw Mufflers
    • Fits 2015-2017 GT Fastback Mustangs

    Review & Installation Video

    Review & Install Video

    Hey everybody, I'm Justin with AmericanMuscle.com and welcome to my quick breakdown of the Flowmaster Outlaw Series Catback Exhaust System, available for your 2015 Mustang GT. As you all just heard, the Outlaw's going to deliver that signature, aggressive Flowmaster sound, thanks largely in part to the patented Outlaw Series mufflers here, one of the loudest offered by Flowmaster, in addition to the removal of the factory resonator. The Outlaw Series mufflers here were actually born and bred for racetrack purposes, where the demand for a lightweight, free-flowing muffler was needed, to tame those crazy volume limits of the open headered sprint cars. Now, this thing became so popular that Flowmaster started incorporating it into some of their more mainstream, consumer exhaust systems, and as a result, it's been one of their top sellers ever since. Replacing that big, goofy suitcase-style resonator here, you're going to find Flowmaster's patented scavenger-style crossover pipe, which is going to take the place of a more traditional X or H pipe. Now, according to Flowmaster, this thing actually produces a little bit more low-end torque than some of those more conventional mid-pipe designs, and it's something that you're going to find with the majority of the Flowmaster Catbacks available for your Coyote-powered Mustang. Getting into some of the details here with the Flowmaster Outlaw Series Catback, you're going to find a full 100% stainless steel construction throughout, three-inch mandrel bent tubing, in addition to these Outlaw Series mufflers here, which as you can see, are done up in the Flowmaster traditional black. Finally guys, four-inch slash cut tips here, embossed with that Flowmaster logo. Unlike the majority of other catback offerings for the 2015 Mustang, there is a small amount of cutting needed to get the Flowmaster Outlaw Series Catback bolted up to your ride. So with that said, be prepared to break out the Sawzall and the eye protection when it comes time to get down to business. Thanks to Flowmaster's detailed instructions, they lay out everything where you need to cut, and you can expect to be making noise in less than three hours from start to finish. So if you're one of the many Mustang owners out there who swear by the Flowmaster name, then be sure to check out the aggressive sounds of the Outlaw Catback for your GT right here at AmericanMuscle.com.

    Super Aggressive Flowmaster Sound. Give your coyote powered S550 Mustang Fastback that unmistakable Flowmaster sound with the Outlaw Series Cat-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.

    Race Car Growl. The included X-Pipe not only helps increase power, but it also adds a loud raspy, race car growl to the sound of your exhaust with its modern "X" crossover pipe design.

    Stainless Steel Construction. Constructed from durable 3" 16 gauge 409 stainless steel tubing for it's corrosion resistant properties the Flowmaster Outlaw Cat-Back features two 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.

    Application. This Flowmaster Outlaw Series Cat-Back exhaust system is designed to fit the 2015-2017 GT Fastback Mustangs equipped with the coyote 5.0L DOHC V8 engine. Not compatible with convertibles. Reuses the stock hangers for installation.

    Fitment: 2015 2016 2017 Details

    CA Residents: Warning: California's Proposition 65

    What's in the Box
    • (1) Right muffler assembly
    • (1) Left muffler assembly
    • (1) X pipe assembly
    • (1) Right intermediate pipe
    • (1) Left intermediate pipe
    Installation Info
    Tech Specs
    Cat-Back Exhaust Specifications
    Piping Material: 409 Stainless Steel Tip Material : Polished Stainless Steel
    Piping Size: 3" Tip Size: 4.0"
    Muffler Type: Straight-through Fitment: 2015-2017 GT Fastback
    Will it fit my Mustang?

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    Questions & Answers (13)

    5 Top Rated Questions

    I have put this exhaust in my 2016 mustang 5.0, and I have noticed that my fuel economy drop down by half, is that normal or do I need something to fix this like a good air intake kit ?

    • A cat-back exhaust will not play any part in fuel consumption. Due to the change in the exhaust sound, that can make you stay in the gas longer than you normally are but cold air intakes along with a tuner can be a good remedy for fixing fuel consumption.

    Helpful (1)

    Can an H Pipe be used instead of an X Pipe for this product? And do you have any recommendations on a compatible H Pipe if so?

    • At this time we are unaware of any H-Pipes that are compatible with the Flowmaster Outlaw Cat-Back Exhaust.

    Helpful (0)

    If I get an x-pipe with for my v6 mustang can I get a shop to weld this gt exhaust to my 2017 v6 mustang?

    • This Flowmaster Outlaw Cat-Back Exhaust is designed for the GT's only, however, if your shop is cutting and welding this unit, it can be made to fit.

    Helpful (0)

    any horse power gain from a 3in cat back

    • Hello, increasing the diameter of the exhaust and freeing it up to flow better will provide a boost in power. These coyotes like to breath so all the better to open them up a bit.

    Helpful (0)

    Will I have to do some cutting for this to fit my 15 mustang? I saw two people comment in the reviews saying that they had to.

    • Some is some cutting required to your factory exhaust but do not worry as Flowmaster has instructions that come with this exhaust that will guide you to the proper cut and install.

    Helpful (0)
    Post Your Question
    8 More Questions
    Will this fit on a European spec GT Fastback, the right hand drive model? 1 answer
    Can this exhaust fit with long tube headers and if so what headers will fit this? 1 answer
    Is an o2 extension kit required for this catback? 1 answer
    Will this setup bolt on to kooks long tube headers 1 7/8 off-road catless headers? 1 answer
    Can anyone recommend a good set of headers that would compliment this exhaust? Thanks 1 answer
    Will this setup bolt on to a set of long tubes?? 1 answer
    Does this exhaust require a tune? I know its always recommended, but last time my x pipe was really raspy, and after the tune it calmed down. Wondering if this is the same case. Thank you 1 answer
    I am looking at getting an S550 Mustang soon and I had this same catback on my 2013 GT before trading it. The issue I had with the outlaw is that it produced a horrible drone around 1900-2000rpm. Does this set up still have that same drone? 2 answers

    People Who Bought This Item Also Bought

    Customer Reviews (44) Write a Review

    Overall Rating 4.8

    out of 5 stars

    Installation Time:Full Day

    Installation Cost:$100-$250

    • Loudness / Volume 5 5
    • Exhaust Note 4.809524 4.8
    • Fit & Finish 4.690476 4.7
    • Bang For Your Buck 4.761905 4.8



    • 5/5

      Installation Time: Shop Install

      Installation Cost: $100-$250

      October 24, 2018

      Best Exhaust System

      If you want that old school muscle car sound this the product for you notice a increase in performance from the beginning

      QuentinL

      Year: 2015 Submodel: GT

      Helpful (1)

    • 5/5

      Installation Time: Afternoon

      September 17, 2018

      Face Melters

      This exhaust produces rich, deliciously audible notes that will have you more worried about smiles per gallon as you gulp up apex after apex. Burble, check. Growl, check. Envious bystanders, check. You’ve seen the YouTube videos. You already know you’re buying it. Just do it already.

      Joe

      Year: 2017 Submodel: GT

      Helpful (3)

    • 5/5

      Installation Time: Afternoon

      August 16, 2018

      It sounds like freedom

      Picture George Washington singing the National Anthem while crossing the Delaware. Thats what it sounds like everytime you get on it. This exhaust is loud, in your face, and does not care about the people around you. Absolute must have for any mustang owner who loves to announce their presence. Side Note: There is a decent amount of drone cruising in 6th Gear at 2K. Its a trade off but I am more than happy to pay it to have my car sounding as amazing as it does.

      kiszler

      Year: 2015 Submodel: GT

      Helpful (3)

    • 5/5

      August 16, 2018

      Worth every penny!

      Full Review/Expereince with some tips. Shop install takes an hour and a half. From what they told me the fit was very well and they had no trouble with it (comes with instructions) and charged me $60. So if your shop tells you they’re having trouble they might not know what they’re doing. First start up after the install is extremely intense, you really get that aggressive sound you’re looking for so you should be extremely satisfied as the video doesn’t do the sound any justice, I was honestly shocked. People will definitely be breaking their necks trying to find the monster they hear driving down the road, it sounds that amazing! With that being said, the drone is absolutely killer, so don’t put this on something you’ll be driving every single day or you’ll regret. I drive my CS/GT around 10 miles a day on average. If you drive your GT over 40 miles/day you should really consider looking at something else because it feels like you’re in a commercial jet and will leave your head busting after a moderate drive. Avoid 100 mile drives at all costs! I’ll clear this up on a final note for those that live in an apartment or anywheres where you have a lot of neighbors. Expect complaints, yeah, seriously. I’m in an apartment while at college and the cold start blares so loud that I feel the need to hop in the car and get out of there as quickly as possible so break this in with your neighbors and tell them you’re not being this loud on purpose and hope they’re nice and understanding like mine because you’ll be heard within a 40-50 yard radius, no exaggeration. Summarized : If you’re worried about being too loud in your quiet neighborhood and take long daily drives, sorry to say but this won’t be for you, just a friendly warning. If not then this will be the best exhaust system you could ever have on your mustang!

      KJ

      Year: 2016 Submodel: GT

      Helpful (2)

    • 1/5

      Installation Time: Afternoon

      July 24, 2018

      Outlaw Catback

      Without going on a long rant, I’ll break it down nice and easy. The exhaust sounds amazing, high quality materials. The fitment is trash, I cut precisely as directed per the instructions and played endlessly with the exhaust and can not get the exhaust tips to line up for the life of me. I took it to multiple exhaust shops and they can not line the tips either, they stated kits are always like this. I would recommend just buying the mufflers and getting a custom exhaust built for better fitment than this kit.

      Daniel

      Year: 2017 Submodel: GT

      Helpful (4)

    • 5/5

      Installation Time: Afternoon

      July 06, 2018

      Great Exhaust

      I was looking for something that would be loud and unique and I found it. This was amazing its super loud but also sounds really amazing. Much better than the factory exhaust. It took some time to install because had forgotten that I needed to cut off some of the old pipe. Just make sure if you get this you are aware you won't be able to go back to the stock exhaust because you have to cut some of the pipe off.

      LawsonW

      Year: 2016 Submodel: GT

      Helpful (2)

    • 5/5

      Installation Time: Shop Install

      May 22, 2018

      Best sounding exhaust ever!

      had this system installed on my 727hp Roushcharged '17 GT. Everything I wanted in an exhaust system. Loud. Obnoxious. And when I drive to town everyone knows it. I didnt buy a supercharged Mustang to please anyone but me. And the way the outlaw catback makes my GT sound...is pure fun. I dont care what anyone tells you, This is the best bang for the buck exhaust out there.

      EARACHE

      Year: 2017 Submodel: GT

      Helpful (4)

    • 5/5

      Installation Time: Shop Install

      Installation Cost: $100-$250

      May 08, 2018

      The Outlaw

      I had the system installed at a local shop that a friend made me aware of and had it installed in my 2017 GT for $120.Designed for sprint cars it is on the loud side at higher RPM's.There is a slight drone at highway speeds but since installing them I've gotten MANY compliments on the sound of the exhaust.If your looking to wake up your GT this is a great mod !!

      ShawnL

      Year: 2017 Submodel: GT

      Helpful (3)

    • 5/5

      Installation Time: Afternoon

      April 23, 2018

      Absolute Beast

      I ordered my Flowmaster Outlaws on a Monday afternoon, they were delivered on Wednesday, and by Thursday afternoon my 2017 GT was turning heads. I couldn’t be more pleased. The sound is a deep growl and is better than I imagined.

      Mike

      Year: 2017 Submodel: GT

      Helpful (2)

    • 5/5

      Installation Time: Less than 1 Hour

      March 24, 2018

      Exhaust

      Louder than the video buy it turns heads and breaks necks at times.

      MarkD

      Year: 2016 Submodel: GT

      Helpful (2)

    • 5/5

      Installation Time: Shop Install

      Installation Cost: $100-$250

      March 13, 2018

      Amazing sound! The way the 5.0 should sound.

      This has a very nice aggressive sound very loud. Other reviews had some points in there about the drone, but honestly it’s not bad at all, barely noticeable. If you want to turn heads and have that nice distinct sound I suggest going with the outlaws. Definitely worth it. Shop install was in between 2-3 hours, wasn’t in any hurry that day anyways. $150 was the price.

      MambaDavid24

      Year: 2017 Submodel: GT

      Helpful (2)

    • 5/5

      Installation Time: Afternoon

      March 02, 2018

      RAW OUTLAW

      Me and a buddy installed these on my 17 GT S550 In about an hour and a half. Tips are a pain to get perfect. Other than that it was pretty basic. Definitely worth it! I originally was going to go with a different system...less aggressive. SO glad I didn't. I can honestly say I have not heard anything louder or better. I read up on multiple systems and am positive I made the right choice for me. I will say this, these are NOT for everyone. They are LOUD! The drone isn't as bad as others say...at least for me. However I can understand the claims. It all depends on the individual. I personally LOVE everything about it. Bottom line...if you want the nastiest sound around these are it. Go big or go home!

      MatH

      Year: 2017 Submodel: GT

      Helpful (3)

    • 5/5

      Installation Time: Less than 1 Hour

      January 31, 2018

      Flowmaster with Corsa Double X Pipe

      I have this Flowmaster connected with the Corsa Double X pipe and there’s no comparison to the Standard flowmaster set up. If you have this already, get The Corsa Double X pipe connected to it. So much better than this as is.

      CarmineB

      Year: 2017 Submodel: GT

      Helpful (2)

    • 1/5

      Installation Time: Shop Install

      Installation Cost: $100-$250

      December 29, 2017

      Ruined My Stang

      The review section for this product really let me down. I was looking for the deep muscle car sound of long ago, and I was sadly disappointed in this cat back system. Going from stock to this resulted in pressure inside the cabin around 2000 rpms that was incredibly painful to drive in. The drone is insane, much worse than other Flowmasters I have owned. BEWARE, there is no video that will describe the drone, as the low frequency will not come through accurately on any video. My brother commented that he felt as if he had been "punched in the earhole" after a short test drive. Not what you want happening to the passengers/drivers in the car. Do not put this system on a daily driver.....you have been warned. No noticeable throttle response improvement. This cat back system was professionally installed and then subsequently checked for a bad installation by a Ford service center. Uninstalled and sold on Craigslist for a loss after less than 50 miles. Don't ruin your new Mustang like I did. Stay away from this cat back system.

      JamesG

      Year: 2017 Submodel: GT

      Helpful (5)

    • 5/5

      Installation Time: Less than 1 Hour

      December 01, 2017

      Holy drone Batman!!!

      This exhaust, hands-down, has completely transformed my cars attitude!! I absolutely love it!!! The drone is pretty intense but I personally don't mind. Everyone that hears my exhaust, even other Mustang owners, are asking me what it is because it sounds fantastic!!! Most of the drone is easily fixable with some Dynamat.

      Joe

      Year: 2017 Submodel: GT

      Helpful (2)

    • 5/5

      Installation Time: Afternoon

      November 02, 2017

      Amazing

      Took these to a local shop and they installed them, took maybe 3 hours total. This exhaust is extremely LOUD! I never expected how much of a difference these could make. Don't buy these if you don't want to wake up your entire neighborhood!

      Brian

      Year: 2017 Submodel: GT

      Helpful (2)

    • 5/5

      Installation Time: Afternoon

      October 30, 2017

      I love it !!!

      Great sound it is loud but just right it may seem like fuel economy is worse but its really you that you always want to hear so you rev it higher it was easy to install going to need a helping hand but took me about 3 hours worth the money !

      JOEYM

      Year: 2016 Submodel: GT

      Helpful (2)

    • 4/5

      Installation Time: Less than 1 Hour

      October 17, 2017

      WOW

      I recommend doing the custom catback, Buy the Scavenger Series X-pipe and then the Axelback Outlaw, its all direct bolt on so no need to cut.. I had the Outlaw on my 2015 GT supercharged, and It was VERY LOUD. No youtube video will justify the sound you need to hear it in person. So overall.. great price and amazing sound. Now for the bad... THE DRONE IS SO BAD! about 2k there is no way to have a conversation without yelling. Really gets a bit too much. if you wanna wake the neighborhood and turn heads when you drive.. get the outlaw.

      Shy

      Year: 2015 Submodel: GT

      Helpful (4)

    • 5/5

      Installation Time: Shop Install

      September 24, 2017

      Awesome

      Great sound. Very loud. I shopped for 2 months before I chose these. Wouldn't want any other ones.

      JefferyL

      Year: 2017 Submodel: GT

      Helpful (3)

    • 5/5

      Installation Time: Afternoon

      September 21, 2017

      This kicks butt

      My wife's car sounds unbelievable! So bad ... I would highly suggest getting this for your ride. I love it

      JohnW

      Year: 2017 Submodel: GT

      Helpful (3)

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