Free Shipping On Orders Over $49. Details

Talk to a Mustang Expert
1-877-887-1105
Every day 8:30AM EST - 11:00PM EST
Win 1 of 2 $15,000 Mustang Builds! Enter To Win!

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

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

$982.38

FREE Shipping

  • Item 387145
  • MPN# 817734

Local Install Shops

Quoted installation from $125

View 3 Shops

near 19355 (change)

Sorry, please enter a valid US or CA postal code
We're sorry, zip can't be updated at this time.

Will this fit your Vehicle?

In Stock Ships same business day.
Ship to: ASHBURN - 20146
Sorry, please enter a valid US or CA postal code
We're sorry, zip can't be updated at this time.
    Create a list
    Add to New List

    Saved - View your saved items

    We're sorry. We couldn't save this product at this time.

    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

    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?

    You Might Also Like

    Customer Photos (11) Submit Your Photo

    View All 11 Photos

    More Products You Might Like

    13 Questions / 14 Answers

    Ask a Question

    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 ?

    JaiA

    • 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.

      KevinD92

    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?

    AdrianA

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

      AMRobD

    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?

    JaewonL

    • 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.

      AMJEFF

    Helpful (0)

    any horse power gain from a 3in cat back

    peppersam

    • 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.

      Ryan H

    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.

    Anonymous

    • 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.

      KevinD92

    Helpful (0)

    Will this fit on a European spec GT Fastback, the right hand drive model?

    Anonymous

    • This is only confirmed to fit on Euro spec GT fastbacks. As long as the underbody is the same as the US spec Mustangs, this may be compatible. Please contact your local Ford dealer for further information.

      KevinD92

    Helpful (0)

    People Who Bought This Item Also Bought

    Customer Reviews (39) 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 4.783784 4.8
    • Fit & Finish 4.756757 4.8
    • Bang For Your Buck 4.837838 4.8



    • 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 (1)

    • 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 (3)

    • 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 (1)

    • 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 (1)

    • 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 (1)

    • 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 (1)

    • 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 (1)

    • 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 (1)

    • 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 (1)

    • 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 (2)

    • 5/5

      Installation Time: Afternoon

      August 25, 2017

      Flowmaster

      Easy to install loud system just wish they gave 2 more clamps with kit

      Shannon

      Year: 2017 Submodel: GT

      Helpful (1)

    • 5/5

      Installation Time: Less than 1 Hour

      August 24, 2017

      Very nice sounding exhaust system.

      Very nice product. Very well made. I am very happy with my purchase

      CodyM

      Year: 2017 Submodel: GT

      Helpful (2)

    • 5/5

      Installation Time: Afternoon

      July 27, 2017

      awesome sound

      This was a great purchase for the money, the sound is awesome. Everyone that hears it loves it.

      MustangMike

      Year: 2017 Submodel: GT

      Helpful (2)

    • 5/5

      Installation Time: Less than 1 Hour

      June 29, 2017

      Refined tone, but still loud

      This was a spectacular purchase as the previous owner of my 2015 Musang GT Premium PP had done a muffler and resonator delete which was god awful loudness from the exhaust. The Flowmaster American-Outlaw cat-back system refined that noise but still lets me make some noise.

      804rvaBEST

      Year: 2015 Submodel: GT

      Helpful (4)

    • 5/5

      Installation Time: Afternoon

      June 15, 2017

      Incredible Sound

      If you're looking for a well made exhaust that is cheaper than others and is loud, I mean REALLY loud, this one is the one to buy. Small modification to the factory pipes is needed (cut about 11 inches out from the cats) but other than that, the fit is superb. There is some drone in the 2k RPM range, but the sound this exhaust produces is one of the best, especially in the 4500 - 6500 RPM range. Would recommend to anyone looking for an aftermarket exhaust for their S550.

      Greg

      Year: 2015 Submodel: GT

      Helpful (2)

    Related Mustang Categories