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Flowmaster American Thunder Cat-Back Exhaust (15-19 EcoBoost w/o Active Exhaust)

AmericanMuscle no longer carries the Flowmaster American Thunder Cat-Back Exhaust (15-19 EcoBoost w/o Active Exhaust). Please check out 2015-2019 Mustang Cat-Back Exhaust for an updated selection.
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Features, Video & Details

  • Aggressive Flowmaster Outlaw Series Sound
  • Durable 409 Stainless Steel Construction
  • 3" Mandrel-Bent Tubing - (Steps Up from 2.5")
  • 4" Polished 304 Stainless Steel Tips
  • Includes Two Flowmaster Outlaw Series Mufflers
  • Made in the USA
  • Not Compatible with Active Exhaust
  • Fits 2015-2019 EcoBoost Mustangs

Review & Installation Video

Review & Install Video

Hey everybody, I'm Justin with AmericanMuscle.com, and this is my detailed review of the Flowmaster American Thunder Series catback exhaust, available for your 2015 and up EcoBoost powered Mustang. You should be checking out the American Thunder catback from Flowmaster if you're after one of the loudest and most aggressive systems for your S550 EcoBoost, that also happens to be one of the most affordable. Now as you guys heard, you're getting every bit of turbo four-cylinder noise out of this system, from the loud and raspy tone, loads of turbo noise, even some pops and backfires on d-cell, so if you're into all that sort of thing, hang out with me for a little bit as we break this system down a little further. Sticking with the sound here a little bit more, since this is an exhaust, after all, now as you guys heard with your own two ears, this thing is going to deliver some pretty aggressive tone. In fact, probably one of the most aggressive systems I've personally heard for the EcoBoost cars. And that's going to be due to the Outlaw Series mufflers that are incorporated into the American Thunder Series catback here. We've had a ton of experience with this muffler here at AM, used it on a bunch of cars, and it's going to be one of Flowmaster's most aggressive systems they offer. Now again, you heard the sound clips guys, easy four out of five. I'm even willing to go up a notch and peg the scale here at a full five out of five on my one-to-five, or one-to-wake-the-neighbors scale. Again, if overall volume is what you're after, then this thing should be on your short list. Shifting gears away from the tone, guys, let's talk about the build with this thing here. Now even though the Flowmaster is traditionally going to be one of your more affordable options when it comes to EcoBoost catbacks, you're still getting a pretty solid build overall, 409-grade stainless steel throughout, including the 16-gauge tubing, starting off with 2 1/2-inch mandrel bends here at the Y-pipe before flaring up to a full 3-inch portion with the axle back section here. Now again, we are including the Outlaw Series mufflers with this system. They are finished off in the Flowmaster traditional black paint, and everything's exiting out the 4-inch slash cut tips, embossed with the Flowmaster logo. Now as you guys heard me say earlier, this thing is pretty affordable in the big picture, and that's pretty much true. It's going to be more of a value or entry level catback, landing you somewhere in the $700 to $800 range, and that puts it right in line with some of the MBRP and Gibson options here on the site. Now your next step up would be to go to a Stainless Works, for instance, or even a Magnaflow, even go to a BORLA, but all those options are going to ring you up for a $1,000-plus. When it comes time to get this thing bolted up to your ride, expect a very simple and straightforward job, guys, one out of three wrenches on my overall difficulty meter here, maybe an hour or two in the garage or driveway. Now no cutting, no permanent modification needed whatsoever, a full bolt-on job here at the Flowmaster. Now an extra set of hands would be nice, but not necessary, as that factory exhaust system is all one piece and can be a little cumbersome to drop by yourself. Other than that guys, though, everything is done underneath the car, so expect to have your race rams, jack and jack stands ready to go, or a lift before getting started. Simply put, guys, if you're looking to make a lot of noise for not a lot of money, then you'll definitely want to check out the American Thunder Series catback from Flowmaster, right here at AmericanMuscle.com.

Classic Flowmaster Sound. Add the unmistakable Flowmaster sound to your S550 EcoBoost Mustang with an American Thunder Series Cat-Back Exhaust System from AmericanMuscle. This catback system improves exhaust flow using Flowmaster's Outlaw Series mufflers, offering the aggressive muscle car exhaust note your high powered Pony deserves.

Stainless Steel Construction. Manufactured in he USA from durable 3" 16-gauge 409 stainless steel tubing for its corrosion resistant properties, the Flowmaster American Thunder Cat-Back features Outlaw Series mufflers with massive 4.0" diameter polished 304 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 American Thunder Series Cat-Back exhaust system is designed to fit both fastback and convertible 2015-2019 EcoBoost Mustangs without the Active Valve Exhaust. Reuses the stock clamps for installation.

Fitment: 2015 2016 2017 2018 2019 Details

MPN# 817750

CA Residents: WARNING: Cancer and Reproductive Harm - www.P65Warnings.ca.gov

What's in the Box
  • (1) Right muffler assembly
  • (1) Left muffler assembly
  • (1) Right tailpipe assembly
  • (1) Left tailpipe assembly
  • (4) Clamps
Installation Info
Tech Specs
Cat-Back Exhaust Specifications
Piping Material: 409 Stainless Steel Tip Material : Polished 304 Stainless Steel
Piping Size: 2.5" to 3" Tip Size: 4"
Muffler Type: Straight-through Fitment: 2015-2017 EcoBoost
Will it fit my Mustang?

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Questions & Answers (13)

5 Top Rated Questions

Would this cat-back exhaust work with the Corsa 3in. downpipe?

  • Yes, this exhaust is compatible with the Corsa 3 in downpipefor the Ecoboost Mustang. 

Helpful (1)

Will this fit on my convertible 2016 eco boost?

  • The Flowmaster American Thunder Cat-Back Exhaust will fit a 2016 EcoBoost Convertible.

Helpful (1)

Will this fit my convertible ecoboost?

  • This Flowmaster American Thunder Cat-Back Exhaust is compatible with both the convertible and coupe models.

Helpful (1)

which exhaust offers less drone? This flowmaster or the Borla S-Stinger for the 2015 ecoboost

  • The Borla stinger cat-back exhaust will offer less drone when compared to the Flowmaster american thunder exhaust.

Helpful (0)

Will this fit an ecoboost premium pony package, trim level 200A?

  • Yes, the Flowmaster American Thunder Cat-Back Exhaust will fit the EcoBoostpremium pony package mustang with trim level 200A without an issue. 

Helpful (0)
Post Your Question
8 More Questions
Is the y pipe on this cat back the same as the flowmaster scavenger y pipe . So if I bought the axle back first and I wanna add sound then I got the scavenger y pipe with that fits the same as a cat back or it need modification 1 answer
is this cat back system CA state legal? 1 answer
Does the cat back system delete the resonator? 1 answer
Will it fits with my convertible ecoboost 2016 ?? 1 answer
Is the exhaust loud inside the car? 1 answer
Would this cat-back be better than the axle-back in terms of sound? 1 answer
I have a 2015 mustang gt convertible. I was looking at the Corsa Catback Sport but then realized it is only compatible with the Coupe. Can you tell me which Catback exhausts will fit the convertible? 1 answer
Does this require any cutting of the stock exhaust? 1 answer

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Customer Reviews (16) Write a Review

Overall Rating 4.6

out of 5 stars

Installation Time:Full Day

Installation Cost:$100-$250

  • Loudness / Volume 4.533333 4.5
  • Exhaust Note 4.8 4.8
  • Fit & Finish 4.6 4.6
  • Bang For Your Buck 4.866667 4.9



  • 5/5

    Installation Time: Afternoon

    January 25, 2019

    Oh my

    Turned my car from zero to hero, best part is it fits the convertible models!

    Nake

    Year: 2017 Submodel: EcoBoost

    Helpful (0)

  • 5/5

    Installation Time: Less than 1 Hour

    November 20, 2018

    Great exhaust

    Great catback especially for the cost. The sound is super aggressive and exactly what I was hoping for. Install was very simple, did It in the driveway in 2 hours, would have been much less if I had a lift. A helper is a must though just for extra hands. Super happy overall

    Brad

    Year: 2018 Submodel: EcoBoost

    Helpful (1)

  • 5/5

    Installation Time: Afternoon

    September 08, 2018

    Sounds amazing - very throaty

    Put this on with a Borla catless downpipe. Love the sound and it's very loud. Sounds throaty, gurgly and deep.

    RobertM

    Year: 2017 Submodel: EcoBoost

    Helpful (1)

  • 4/5

    July 12, 2018

    Wow!

    Was the first thing the kids said at the local ice cream shop we went to after installing it. It’s loud. Kinda drone if your just flooring it and making your way through the gears, but all in all a nice deep sound. Great improvement over stock but then again, anything would be. Installation instructions weren’t bad; images are a bit small and that’s only a problem when trying to figure out which way the y pipe angles towards. On a convertible, which the instructions don’t address, you have no choice but to unbolt all of the bracing under the car. We had tried taking it out without doing so, cutting the old pipes and removing it from either side of the rear suspension, but you can’t get the new one in without taking out the bracing so may as well do it right off the bat. If you have the steeda jacking rails or any rails I’d presume, those need to come out as well. Because of cutting, took us about 3 hours. And I couldn’t imagine doing it yourself without a lift, which we used. A second set of hands is a must, if not just to hold the mufflers when getting them into the y pipe. All in all, very happy.

    Mario

    Year: 2016 Submodel: EcoBoost

    Helpful (4)

  • 5/5

    Installation Time: Less than 1 Hour

    June 18, 2018

    Perfect !!!!

    I just got this exhaust system and I'm not going to lie it sounds incredible, it has a pretty aggressive tone for a 4 cylinder EcoBoost mustang. Some people don't think that is a 4 cylinder because it sounds so nice.

    AlvaroR

    Year: 2015 Submodel: EcoBoost

    Helpful (4)

  • 5/5

    Installation Time: Shop Install

    Installation Cost: $100-$250

    April 06, 2018

    Perfect

    Just replaced the factory exhaust on a 2015 eco boost with 9k miles and garaged kept. My baby of course...Love this system. Gives it the perfect sound and now the exterior mods fit the sound. Definite increase in HP and torque. Having the Flowmaster cold air intake installed this week and excited to see the difference that makes.

    JarrodK

    Year: 2015 Submodel: EcoBoost

    Helpful (3)

  • 5/5

    Installation Time: Shop Install

    Installation Cost: $100-$250

    March 28, 2018

    Flowmaster

    Great sound great performance!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

    MarkG

    Year: 2017 Submodel: EcoBoost

    Helpful (3)

  • 5/5

    Installation Time: Less than 1 Hour

    July 20, 2017

    flowmaster catback

    took around an hour to do, very happy with it, only complaint is the the pipes were touch the sub frame.

    AliV

    Year: 2016 Submodel: EcoBoost

    Helpful (6)

  • 4/5

    Installation Time: Shop Install

    Installation Cost: $100-$250

    March 07, 2017

    Great sounding Pipes

    The american thunder exhaust is a loud sounding, head turning, and great aftermarket exhaust for anyone looking to have their pony wake the neighbors or be recognized on the streets, from its idle rumble to the high rpm roar is really something to listen in person. I've listened to sound clips in deciding which exhaust to get but after going with these and finally getting to hear in person boy is it loud. I would've given a 5 but i was given 2 clamps instead of 4 clamps that was listed in whats in the box. other than that its worth it!

    DJamesThompson

    Year: 2017 Submodel: EcoBoost

    Helpful (6)

  • 1/5

    Installation Time: Less than 1 Hour

    February 26, 2017

    Flowmasters

    The price is right, the install was easy, and the sound is great! I love the sound at super low Rpms when you're in a parking garage, and stepping all the way on the gas when you're in a tunnel. Sounds great and roars . Still sounds like a 4 banger to me but it's nothing like a Honda or Toyota. The only downside is that it comes in two pieces and you need to get them welded together if you have a convertible or else it will sag and contact a brace under the stang causing it to rattle. Perfect choice for me because I wanted something low priced and loud and this is what I got.

    MichaelT

    Year: 2015 Submodel: EcoBoost

    Helpful (8)

  • 5/5

    Installation Time: Shop Install

    Installation Cost: 0-$100

    November 09, 2016

    Flowmaster outlaw frees the pony

    Very great buy. I was worried that the sound would be like a Honda or Toyota with aftermarket exhaust. But to much suprise my muffler guy said it reminded him of a small engine Ferrari. He expexted the pitch to get higher in the upper rpms but it did just the oppisite. The higher the rpms the deeper the sound. Great buy well worth the money. Easy install as well.

    Shegrowls

    Year: 2016 Submodel: Ecoboost

    Helpful (7)

  • 5/5

    September 05, 2016

    Everything I wanted!!

    Exhaust have such a huge performance boost for my ecoboost. So much louder and aggressive and makes a mustang really sound the way it's supposed to sound. Shipping was very fast and couldn't be happier.

    Rob23

    Year: 2016 Submodel: Ecoboost

    Helpful (5)

  • 5/5

    Installation Time: Afternoon

    June 28, 2016

    Noise is the killer

    The best cat back system I have ever purchased....

    Sunny

    Year: 2016 Submodel: Ecoboost

    Helpful (4)

  • 5/5

    Installation Time: Afternoon

    May 05, 2016

    THE NOISE!!!!

    Holy moly. I knew it would be loud but, man. So the install can be done solo with just some ramps and a jack. Not very easy but it can be done. The sound from this thing will wake the neighbors, the dogs, the cats, the dead you name it. Even though it's a four cylinder, the sound is definitely FLOWMASTER and good, deep and aggressive. A

    Josh2013

    Year: 2016 Submodel: Ecoboost

    Helpful (7)

  • 5/5

    Installation Time: Shop Install

    Installation Cost: 0-$100

    March 20, 2016

    Much Needed

    This is much needed to all Ecoboost owners who's trying to wake up there ride its loud its everything i wanted from my Ecoboost. The install was done by my local muffler shop cost about 85 bucks and took no longer then 2 hours, from the moment you turn on the car you will think you hoped in the wrong car because I didn't believe it myself, from the growl from the start to the screaming sound when you gun it this exhaust is perfect and at the perfect price range I would recommend this to all ecoboost owners that are looking to wake up there ride!!!

    MarioDL

    Year: 2016 Submodel: Ecoboost

    Helpful (4)

  • 4/5

    Installation Time: Afternoon

    December 12, 2015

    Good value

    Installed by myself in the garage with car on jack stands in a couple of hours. Hardest part was removing the stock exhaust. I would definitely recommend a second person to help remove. Installation was straight forward but I did have to use a cone to fix one muffler inlet that was slightly bent in shipping. System was not packed very well. Tips were protected but that was all. I touched up the mufflers with black a paint before installing. Great sound and good price.

    strommer

    Year: 2015 Submodel: Ecoboost Fort Worth, TX

    Helpful (5)

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