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Flowmaster American Thunder Cat-Back Exhaust w/ X-Pipe (13-14 GT)

Market Price $971.99 You Save 12% ($112.26)
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$859.73

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  • Item 18446
  • MPN# 817587

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    Features, Video & Details

    • Aggressive Flowmaster 60-Series Delta Flow Sound
    • Durable 409 Stainless Steel Construction
    • 3" Mandrel-Bent Tubing
    • 4" Polished Stainless Steel Tips
    • Includes Scavenger X-Pipe And Two Flowmaster 60 Series Mufflers
    • Fits 2013-2014 GT

    Review & Installation Video

    Review & Install Video

    Hey I'm Justin with AmericanMuscle.com, and I'm breaking down Flowmaster's American Thunder Catback exhaust, fitting the 2013 Mustang GT. Flowmaster offers a number of mufflers all with their own unique tone, in this case the American thunder for your GT Mustang is built around the iconic 60 series delta flow mufflers. These mufflers make this kit the perfect choice for the Mustang owner who is looking for an exhaust that will be relatively mild around town, yet still offer a good amount of bite whenever you get on the pedal. As a matter of fact I like to compare this exhaust to the Magnaflow street series, both offer a tone that's slightly more aggressive than stock, but without having to worry about waking up the neighbors, or getting the attention of Jonny Law. Besides these two 60 series mufflers, this system also boasts stainless steel construction throughout, including mandrel bent 3" tubing from tip to tip. It also features Flowmaster's unique scavenger style crossover pipe, which they say is great for picking up a little extra torque. Those 60 series mufflers are finished off in Flowmaster's signature black coating, which is great at resisting corrosion, and then finally, everything's going to exit out these two 4" polished tips. Since this is a Catback you can expect to spend about 2 hours underneath the car getting everything bolted up, but since there's no cutting required whatsoever you should be able to handle it using basic hand tools. Now let's hear how Flowmaster's American Thunder sounds compared to our factory exhaust.

    Signature Flowmaster Sound. Give your coyote Mustang that unmistakeable Flowmaster sound with the American Thunder Cat-Back Exhaust system from AmericanMuscle. The Flowmaster American Thunder Cat-Back Exhaust with its mandrel bent tubing will greatly improve your Mustangs exhaust flow for an increase in power, and the included 60 Series Delta Flow Mufflers will improve your exhausts sound for a deep aggressive muscle car exhaust note.

    Race Car Growl. The included Scavenger 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.

    Reuses Stock Cats. The included Flowmaster Scavenger X-Pipe bolts up directly behind the stock catalytic converters with no cutting required saving you time and money. By reusing your stock catalytic converters, you ensure that your Mustang is smog-legal.

    Quality Construction. Constructed from durable 3" 16 gauge 409 stainless steel tubing for it's corrosion resistant properties the Flowmaster American Thunder Cat-Back features two 60 Series Delta Flow American Thunder 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 American Thunder Cat-Back exhaust system is designed to fit the 2013-2014 5.0L coyote Powered GT Mustang equipped with either aftermarket shorty headers or the stock manifolds. Does not fit Shelby GT500 models.

    Fitment: 2013 2014 Details

    What's in the Box
    • (1) Right muffler assembly
    • (1) Left muffler assembly
    • (1) Scavenger X pipe assembly
    • (1) Right intermediate pipe
    • (1) Left intermediate pipe
    • (4) Band clamps
    • (2) Hanger keepers
    Installation Info
    Tech Specs
    Axle-Back Exhaust Specifications
    Piping Material: 409 Stainless Steel Tip Material : Polished Stainless Steel
    Piping Size: 3.0" Tip Size: 4.0"
    Muffler Type: Chambered Fitment: 2013-2014 GT
    Will it fit my Mustang?

    Customer Photos (4) Submit Your Photo

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    6 Questions / 7 Answers

    Ask a Question

    Will these fit with long tube headers?

    BrodyB

    • The Flowmaster American Thunder Cat-Back Exhaust with X-Pipe will not be compatible with long tube headers.

      AMRobD

    Helpful (0)

    Will this exhaust work with longtube headers?

    Andy

    • Hi, This Cat-Back will only work with aftermarket shorty headers or the stock manifolds.

      Chris J

    Helpful (0)

    Will this fit my 2012 GT? This (http://www.americanmuscle.com/flowmaster-american-catback-1112gt.html) us the 2012 gt model, but it isn't in stock and looks virtually identical to the 2013 version.. is there a real difference?

    ChuckSkyline

    • There are some slight differences between the 12 and 13, though almost unnoticeable to the naked eye. In terms of your exhaust, the difference will prevent this exhaust from being able to simply bolt up. You can make it work, just expect to make some modifications to achieve it. Although the easier option is to purchase the same exact exhaust but designed for a 12gt: http://www.americanmuscle.com/flowmaster-american-catback-1112gt.html

      JeffAM

    Helpful (0)

    Cause check engine light? Will this system cause the "Check engine" light to come on?

    uttersqueez

    • No it will not cause a check engine light. It does not remove the catylitic converters

      fast5ohh

    Helpful (0)

    Would this exhaust go well with some long tube headers without a problem such as the bbk or pypes longtubes?

    Richeh

    • As long as the long tube headers had the ball socket connection on the end. If not you would probably have to get an exhaust shop to install them

      fast5ohh

    Helpful (0)

    does this only fit on stock or can i get short tube headers and this to bolt on after? i want to get shorty ceramic headers, and an exhaust system all the way back for better flow. will that work?

    Mike12

    • Absolutely! Ceramic Shorty Headers would be a great complement to the American Thunder Catback. Hope this helps!

      LisaS

    Show 1 more answer Helpful (0)

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    Customer Reviews (23) Write a Review

    Overall Rating 4.6

    out of 5 stars

    Installation Time:Full Day

    Installation Cost:$100-$250

    • Loudness / Volume 4.608696 4.6
    • Exhaust Note 4.652174 4.7
    • Fit & Finish 4.217391 4.2
    • Bang For Your Buck 4.521739 4.5



    • 3/5

      Installation Time: Afternoon

      April 14, 2018

      Very raspy

      Great throttle response. Felt like it added a good amount of power, but did not like the way it sounded at all. Very raspy, sounded like a V6. one of my mufflers would vibrate during cold start, sounded like a rattling tin can. Had to get the exhaust tips extended about 1.5 inches. They didn't stick out of the bumper enough (didn't look natural).

      AldoP

      Year: 2014 Submodel: GT

      Helpful (0)

    • 3/5

      Installation Time: Afternoon

      March 31, 2017

      Decent

      Sounds good. Wanted something loud but not too loud. Fitment left a lot to be desired. The passenger side muffler required me to reweld a new hanger on it to line up correctly. Besides that install was basic and straight forward.

      NicholasB

      Year: 2014 Submodel: GT

      Helpful (2)

    • 5/5

      Installation Time: Full Day

      October 05, 2016

      How the 5.0 was meant to sound!

      The American Thunder Exhaust makes the 5.0 sound like it should have from the factory! It's phenomenal. I was looking to give my car that muscle car rumble-a modern version of the sound of my '60s Mustangs, and this did it! My only complaints with the product are: 1) It requires you to reuse two of the factory clamps off of the factory exhaust. I really hated cutting those off of the original exhaust as I wanted maintain it's originality. I'm not sure why Flowmaster couldn't include them. I could not find any suitable aftermarket ones either. 2) My second issue was how difficult it was to adjust the exhaust tips. We spent about two hours trying to get them straight and away from the rear valance. One of the tips still ended up so close to the lip that it vibrated over and rubbed the paint off. I had to get it professionally straightened and the paint fixed. Probably could have been avoided if I had more experience installing exhaust systems, but if you also don't have any previous experience you may want to consider this. The results were exactly what I was trying to achieve though, the car sounds incredible. The very first day I was driving it after the installation, a guy pulled up next to me in a 1966 Corvette and made it a point to roll down his window and tell me how incredible my car sounds! Not the most likely guy to give a Modern Mustang a compliment, so this sound has broad appeal. I highly recommend this product, it's a great value, and it delivers. Just install with care.

      TH

      Year: 2014 Submodel: GT

      Helpful (3)

    • 5/5

      Installation Time: Shop Install

      Installation Cost: $100-$250

      October 01, 2016

      The Perfect Balance

      This is the perfect exhaust for those who want to hear their motor, but not be the annoying guy with obnoxiously loud car. At idle, it's louder than stock, but only slightly and with a deeper tone. Around 2.5-3k rpm, watch out. That's where you hear it- pure music. And it only improves as you go up in the powerband. My only regret is why I didn't put this system on years ago. One word of caution though: the kit fit well, but the tips where not aligned and symmetical. I had the shop that did the install cut the tips off and re-weld them to make them symmetrical. The end results is perfect. In the end, it's totally worth it.

      Tony

      Year: 2014 Submodel: GT

      Helpful (3)

    • 5/5

      Installation Time: Shop Install

      Installation Cost: $100-$250

      June 07, 2016

      Best value out there

      I wanted something that would free up my exhaust without being too loud. I am completely happy with this system. I added the Bama 91 race tune and cut my 1/8th mile race time by .4 seconds. Better than I expected!

      DGC

      Year: 2013 Submodel: GT

      Helpful (3)

    • 5/5

      Installation Time: Shop Install

      Installation Cost: $250-$500

      May 06, 2016

      Sounds so good and you feel the difference.

      I got 2014 GT with cold Intake and tuner wanted to get exhaust ordered this one and when I started it sounded insane. Totally new sounding vehicle. Straight muscle car sound. No drone. Sounds so beautiful. Other them forgetting to send clamps I'm very happy. This what mustang should sounds like.

      Beast

      Year: 2014 Submodel: GT

      Helpful (3)

    • 5/5

      Installation Time: Shop Install

      Installation Cost: $100-$250

      July 20, 2015

      The boy sounds like he"s become a man

      This exhaust is a grade above the stock equipment. Love the roar it creates especially on cold starts and I can't help punching it. Gives me what I felt a Mudtang should sound like.

      Bushmaster

      Year: 2013 Port Reading, NJ

      Helpful (2)

    • 4/5

      Installation Time: Afternoon

      June 07, 2015

      American Thunder Cat Back

      American Muscle shipped fast and arrived in good condition even though the box had little packing material in it. I did this install on a few days ago, started at 430 and didn't finish till 10 pm, taking off the factory exhaust is not easy but that was just the beginning. We put the car high in the air with 4 jack stands and we still had clearance issues getting the flowmaster mid pipes over the axles. I don't recommend trying to install this exhaust unless you have a lift for clearance reasons. Due to the fact that we couldn't get mid pipes over the axle we had to drop the whole rear end to have enough room to complete the exhaust. Once on ,everything fit really well with no more issues. This was a difficult install but it was worth it, the tone of this system is fantastic, slightly louder then stock at idle but even a touch of the gas pedal let's loose this great deep tone flowmaster is known for. As well there is no irritating drone at high way speeds. I recommend this system 100

      Matt

      Year: 2013 Submodel: GT Tampa FL

      Helpful (2)

    • 5/5

      Installation Time: Less than 1 Hour

      May 29, 2015

      Awesome

      Install was quick and easy, perfect sound, a small amount of drone but not enough to bother you, still makes me smile when I get on it

      Geif

      Year: 2014 Submodel: GT Houston, Tx

      Helpful (3)

    • 5/5

      Installation Time: Afternoon

      December 18, 2014

      Nice deep tone

      Perfect fit. Easy to install. Noticable improved throttle response gave my 13 gt the classic "flowmaster" sound. Not raspy at all

      fast5ohh

      Year: 2013 Submodel: GT Logan, WV 25601, USA

      Helpful (3)

    • 5/5

      Installation Time: Shop Install

      Installation Cost: 0-$100

      October 18, 2014

      Cat back exhaust

      This is absolutely 1 of the best things (of many) done to this car. I am able to hear the engine at start up, has a great sound when you get on it, a nice burble when you downshift and no drone. Nothing but compliments from people that have heard it!!!

      rod14

      Year: 2014 Submodel: GT Las Vegas, NV, USA

      Helpful (3)

    • 5/5

      Installation Time: Afternoon

      September 24, 2014

      Gorql in the daily grind

      Its really opens up the sound and gives the car that signature growl that I have come to love on a GT... all while not being to loud for my 30 minute daily commute.

      GCochran

      Year: 2014 Submodel: GT GA

      Helpful (3)

    • 5/5

      Installation Time: Less than 1 Hour

      September 01, 2014

      American Thunder exhaust system review

      I had this system installed by a shop. It took the shop 1/2 hr. to install, no mention of problems. Cost was $150 plus tax. On start up it is fairly loud but at normal idle it's close to the stock sound level. Easy take off and cruising is also close to the stock system. Once you step down on the gas some the sound level goes up, the more you step on it the louder it gets. This system can easily be used on a daily driver, or when taking a long trip. Very nice set up, great value for the money you will not be dissapointed.

      Ken2

      Year: 2013 Submodel: GT Cedar Rapids, IA, USA

      Helpful (2)

    • 5/5

      Installation Time: Shop Install

      Installation Cost: $100-$250

      May 19, 2014

      WOW!!!

      I have always used Flowmaster products on all my vehicles-from Corvettes to pickups!! They have always sounded good and improved performance! But, on my 13 GT it has outdone itself to the max!! It has a low rumble at idle,a great roar on full throttle accel and a nice tone at cruising speeds up to 80 mph!! Best investment I have ever made!! And at steadt hiway speeds has increased my gas mileage to boot!! LOL good deal all the way around!!!

      horsearound

      Year: 2013 Submodel: GT Raeford, NC 28376, USA

      Helpful (3)

    • 5/5

      Installation Time: Less than 1 Hour

      May 06, 2014

      Great sounding exhaust!! It's what a mustang should sound like! !

      I was ify about buying this item because of the bag fitment reviews it received. I thought to myself for the price I'll deal with it. Turns out it went right in with no issues what do ever. I can only imaging those customers did not wait to the end to tighten everything. Great item. I love the exhaust note it has! It's what a 5.0 should sound like! Performance wise I didn't notice any gains but a catback is mainly for sound and not power. I'm all stock except for the catback.

      SlowGrabberBlue

      Year: 2014 Submodel: GT Phoenix, AZ, USA

      Helpful (3)

    • 5/5

      Installation Time: Afternoon

      September 18, 2013

      Great sound with the stock headers and cats!

      Excellent product and this is the first exhaust system that I have purchased for the new 5.0s. I have bought Flowmaster in the past and I was satisfied with the sound and installation.

      Paul74

      Year: 2014 Submodel: GT Cape Coral, FL, USA

      Helpful (2)

    • 4/5

      Installation Time: Shop Install

      Installation Cost: $100-$250

      August 26, 2013

      Sounds Great, but a hassle install.

      I had a shop install this exhaust and i was quoted $65 to $150. i ended up paying the full 150$. I was quoted 2 hours, i got the car back 5 hours later with them stating that the hangars were bent and would allow the exhaust to sit properly and i wanted a better fit than what i had i would have to contact Flowmaster. I contacted American Muscle for warranty assistance but i was told to contact Flowmaster directly I contacted Flowmaster and the rep there had me get a second opinion from one of there authorized dealers. I went and had them adjust the pipes. they ended up cutting one of the tips off and re-welded it, apparently it was welded on at an angle.. Flowmaster was great and offered a full replacement in the event i was not happy with the fix. The sound is great, The fit is okay, i would have like it to fit right the first time with no modification, one tip sets about 3/4" farther out than the other. I purchased this mainly because flowmaster offered at $100 rebate at the time of purchase.

      LVSGMS197

      Year: 2014 Submodel: GT Las Vegas, NV, USA

      Helpful (2)

    • 5/5

      Installation Time: Afternoon

      July 24, 2013

      Sound Awesome!

      The exhaust sounds very nice cruising around and is not overly loud. The fitment was slight off. After installing the exhaust myself and spending hours trying to get it to line up I gave up and took it to an exhaust shop. They took it off and the left side (drive side) pipe was about an 1" off on the bend. They re-bent it and installed it. Now its perfect. Love the sound, but after paying a shop to fix the bend I could have gotten the Borla's. I do recommed this product and imagine it was a 1 in million product defect. I have numerous other Flowmasters and they have been perfect.

      lwevert

      Year: 2014 Submodel: GT Honolulu, HI

      Helpful (2)

    • 4/5

      Installation Time: Shop Install

      Installation Cost: 0-$100

      July 24, 2013

      great sound

      Great product. Only complaint is that there's a slight exhaust leak and I had it professionally installed. No other things wrong other then that

      cookiemonster

      Year: 2013 Submodel: GT pa

      Helpful (2)

      • Response from AmericanMuscle

        If you had it professionally installed, I'd take it back as soon as you can to let them know and have it fixed. If installed properly, there should be no leaking with this stystem.

        Lisa, Customer Care

    • 5/5

      Installation Time: Afternoon

      July 01, 2013

      Best 5.0 exhaust!

      When I first installed this system on my car there was a major fitment issue. I called AM and they sent me a brand new kit! After installing the second system it was perfect. The sound alone makes this exhaust worth the problems. The stainless steel is average quality but none of that matters when you hear the sound it makes! Its not a quiet exhaust but its very pleasant and mellow at low RPM. I would recommend this exhaust over any other system. I'm not sure about power gains as I installed this with a CAI and tune.

      GTEd2013

      Year: 2013 Submodel: GT

      Helpful (3)

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