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Flowmaster American Thunder Cat-Back Exhaust w/ Muffler Relocate (07-18 Wrangler JK)

Market Price $509.99 You Save 13% ($67.02)
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$442.97 (kit)

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  • Item J100311
  • MPN# 817674

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    Features, Video & Details

    • Cat-Back System
    • 409 Stainless Steel
    • Polished Finish
    • Made in the USA
    • Moderate to Aggressive Tone
    • 2.5 Inch Mandrel-Bent Tubing
    • Increased Off-Road Ground Clearance
    • Laminar Flow Super HP-2 Muffler
    • Limited Lifetime Warranty
    • Fits 2007-2018 JK Wranglers

    Review & Installation Video

    Review & Install Video

    I'm Ryan with ExtremeTerrain.com, and this is my review of the Flowmaster American Thunder Catback exhaust system with muffler relocation, fitting all 2007 or 2016 Wranglers. This system will fit both two-door and four-door JKs. You should be taking a look at this exhaust system if you're looking for a little bit more sound out of your JK. This system will provide a lower and a louder exhaust sound. And something I really like about this Catback system over a lot of the axle-back systems that are available on the market is that this will completely relocate the muffler up and out of the way of rocks and other trail hazards. So if you've damaged your factory system and you're looking for a replacement, or you just want that lower, louder exhaust note, this is a good system to take a look at. Flowmaster built this out of 409 stainless, which is a quality stainless steel, but it's not going to quite give you the same corrosion resistance as a 304 stainless. So if you live in an area where they use a lot of salt on the road in the winter, like we do, you might still end up with some corrosion or surface rust with a system like this. All of the tubing is two and a half inch mandrel bent tubing, so you won't have any restriction on the bends, and the whole system is finished off with this nice polish tip. The heart of this system is the laminar flow Super HP-2 muffler. This gives you all of the flow and the sound of the HP-2 muffler in this compact square case, which is nice, because, like we said before, this tucks the muffler up out of the way of the trail hazards so it's not going to get damaged. When you take the system out of the box, you can tell that it is well-built and well-designed, even if the welds on the muffler leave a little bit to be desired, at least visually. Nice thing about this system is that Flowmaster backs you with a limited warranty. You can install this system at home in your driveway. Just keep in mind that the same system is sold for both four-door and two-door JKs, so if you're installing it on a two-door, you will have some cutting to do. The install instructions tell you exactly where to cut and how much. However, after we made that cut, we found that they told us to take off a little bit too much. We also had to do some additional trimming that wasn't in the installation instructions to get our system to fit right. So if you're not comfortable doing that type of cutting and fitting, I would recommend that you take the Jeep to an exhaust shop to have them install the system. If you do decide to install this system yourself, there are a couple things to keep in mind. As with any exhaust system installation, the install time will vary greatly depending on how rusty your stock system is. I would definitely recommend spraying all of the stock clamps and bolts with a good penetrating oil well before you get started. That will definitely speed things up. And those of you who have done exhaust systems in the past will know that the rubber exhaust hangers can be a little bit tricky. I would also recommend lubricating those and having a pry bar handy to pop them loose. This is a high-clearance exhaust system, so it tucks everything up out of the way, and clearance is a little bit tight in some spots. One spot in particular, where the new tubing runs between the sway bar and the rear cross member, is particularly tight. We were able to get our system adjusted so it didn't hit either the cross member or the sway bar, but it took some patience. With the additional trimming and the fine tuning, the entire installation should take about two hours. Once we got this system installed and out on the road, I have to say I really liked the way it sounded. It's definitely a lower exhaust note, and you get a little bit more volume, but you don't get a drone in the cab, which is really nice. We even got a little bit of popping and gurgling during engine braking with our stick shift. This system doesn't just sound good, it's also functional. It tucks everything up out of the way of trail obstacles and rocks. I have to say I do like the way it sounds and the way it functions. But I would have like to see it fit a little bit better right out of the box, especially for a system at this price point. Now there are exhaust systems that we offer that are more expensive, and they don't relocate the muffler, so I would say this is a really good value once you get it installed. So if you're looking for an exhaust system that will give you a lower and louder exhaust note, and tuck all the exhaust components up out of the way of trail obstacles, I would say this is a good choice, even if the install was a little bit challenging. That's my review of the Flowmaster American Thunder Catback exhaust system with muffler relocate, fitting all 2007 and 2016 JKs that you can find right here at ExtremeTerrain.com.

    Construction. Flowmaster's American Thunder Cat-back exhaust system is constructed out of 409 stainless steel for lasting durability. This American made system features a 2.5 inch round, mandrel bent tubing for smooth, unrestricted airflow. Combined with Flowmaster's Patented Laminar Flow Muffler, this system will give your JK a throaty and aggressive tone. This system improves your JK's ground clearance by relocating the muffler up and out of the way of rocks and trail hazards. Experience the trails while enjoying your rig's new sound!

    Application. Flowmaster protects their stainless steel systems with a limited lifetime warranty. This system fits 2007-2018 Jeep Wrangler JK Models.

    Fitment: 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 Details

    What's in the Box
    • (1) Inlet Pipe Assembly
    • (1) Muffler
    • (1) Over Axle Pipe
    • (1) Exit Pipe Assembly
    • (1) Clamp & Hanger Kit
    Installation Info
    Tech Specs
    Will it fit my Wrangler?
    • JK Rubicon 2 Door - 07, 08, 09, 10, 11, 12, 13, 14, 15, 16, 17, 18
    • JK Rubicon 4 Door - 07, 08, 09, 10, 11, 12, 13, 14, 15, 16, 17, 18
    • JK Wrangler 2 Door - 07, 08, 09, 10, 11, 12, 13, 14, 15, 16, 17, 18
    • JK Wrangler 4 Door - 07, 08, 09, 10, 11, 12, 13, 14, 15, 16, 17, 18

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    3 Questions / 3 Answers

    Ask a Question

    I reall like this system for my 2016 Jeep Wrangler jk but my question is will pass inspection without the catalytic converter

    KevinW

    • The Flowmaster American Thunder Cat Back Exhaust will install after the stock cat, allowing you to retain all emissions equipment and pass inspection.

      Rob D

    Helpful (2)

    Is it a loud obnoxious sound when you have the top off?

    MatthewB

    • That would come down to personal opinion. The Flowmaster American Thunder Cat-Back Exhaust is a louder exhaust. We would suggest checking out our review video for sound references. Additionally maybe check with your local Jeep club to see if anyone is running the exhaust to get a in person sound reference.

      XTHelenW

    Helpful (0)

    Will this fit a 2017 Rubicon?

    CrisS

    • Hello! The Flowmaster American Thunder Cat Back Exhaust will fit a 2017 Rubicon.

      VinceXT

    Helpful (0)

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    Customer Reviews (36) Write a Review

    Overall Rating 4.3

    out of 5 stars

    Installation Time:Afternoon

    Installation Cost:$100-$250

    • Exhaust Note 4.5 4.5
    • Fit & Finish 4.25 4.3
    • Bang For Your Buck 4.416667 4.4



    • 5/5

      August 19, 2017

      A few tips

      Great product! I'm very pleased with the results after the install. I own a 2 door with a stick, and have owned other Flow Master exhaust kits for other vehicles in the past, so I pretty much knew that the exhaust notes would be exactly what I was looking for as I went through the gears. So, as for fit on the 2 door. Here is my advice. The instructions will tell you to cut 20.5" off of the pipe that goes over the axle and connects to the outlet side of the muffler. My advice, only take off 20", the first cut gets you a tad closer to weld point for the hanger than I liked. Secondly, I like the guys at Extreme Terrain, (watch the video) had to do an additional cut. No big deal. I found that I still needed to take about 2.5" off of the pipe that went from the "Y" pipe to inlet side of the muffler. In addition, I think this will help everyone greatly. Drop your rear sway bar in addition to the factory armour/skid plate under the transmission/transfer case. This move allowed me to dry fit everything and really helped get the down spout at the rear to fit better. Once you have it all lined up and dry fitted, get the 4 bolts back in for the sway bar before you place the clamps, it's a super tight fit, but I was able to get it perfectly spaced between the frame and the sway bar. Overall, it took me and a buddy 2 hrs and we weren't rushing it. We were joking around more than anything. It does help to have a lift and the proper chop saw for the cuts, that just speeds up the entire process.

      James

      Year: 2016Submodel: Wrangler

      Helpful (7)

    • 3/5

      Installation Time: Less than 1 Hour

      June 11, 2017

      Flowmaster Exhaust

      I installed this product about week ago. If you have minor automotive skills, you can install it. There are detail videos out there on how to install the exhaust system.I installed it in about 45mins. I like the sound of the exhaust, but it might be to loud for some persons. But on a good note, my gas mileage has increased by 3 miles per gallon.

      WhiteWolf

      Year: 2016Submodel: Wrangler

      Helpful (5)

    • 3/5

      Installation Time: Less than 1 Hour

      August 26, 2017

      Great Exhaust

      So as most of you know it's harder to get the factory system off. Very easy installation HOWEVER, the fitment of this system isn't as plug and play as it says. My issue is everything fits perfectly except when you get to the exit pipe. It's not even close to fitting in the stock exhaust mount. Not sure how to fix this. Although the system is for the most part secure a good bump will make some noise. Contacted Flowmaster directly and they are working on a solution.

      JasonD

      Year: 2013Submodel: Wrangler

      Helpful (4)

    • 4/5

      Installation Time: Full Day

      August 16, 2017

      Great sound, tough install

      Love the sound of this muffler, love the clearance space. Installation was not as easy as suggested. I had to grind off a OEM screw on Y joint and cut 1/2" off pipe to make the pipe fit above the rear sway bar.

      DanC

      Year: 2017Submodel: Wrangler

      Helpful (4)

    • 5/5

      July 08, 2017

      Flowmaster!!

      Was little concerned with all the different reviews and different manufacturers. Flowmaster does not disappoint. Sounds great, tight fit, (which I liked) bout 2 hrs to tear old out and install new. Good deal.

      ShawnF

      Year: 2010Submodel: Rubicon

      Helpful (3)

    • 5/5

      Installation Time: Afternoon

      June 16, 2017

      Sounds Awesome

      This exhaust sounds great, it has a deep full sound in low rpms and in high rpms it has a higher tone. Absolutely love this exhaust. It is a little louder than the video shows but is a perfect balance. Keep in mind that if you have a rusted exhaust it will take a while to get off.

      TimothyM

      Year: 2008Submodel: Wrangler

      Helpful (3)

    • 5/5

      October 26, 2016

      Awosome muffler

      Easy to install 2 1/2 hours to do it,very good sounds and more power.

      Bejo

      Year: 2014Submodel: Rubicon Unlimited

      Helpful (3)

    • 5/5

      Installation Time: Afternoon

      October 04, 2016

      Flowmaster exaust install

      Everything went smooth on the install.just had to cut about 1 inch off the pipe after the muffler to get it to fit properly. Sounds great.

      Bikenut61847

      Year: 2016Submodel: Rubicon

      Helpful (3)

    • 5/5

      Installation Time: Afternoon

      August 03, 2016

      Awesome.

      Very easy to install. The hardest part was getting the old exhaust out. Sounds killer also.

      Giveumtheboot

      Year: 2011Submodel: Rubicon Unlimited

      Helpful (3)

    • 5/5

      Installation Time: Shop Install

      Installation Cost: 0-$100

      February 20, 2014

      Flowmaster thunder

      My factory exhausted had rotted out so it was time for a replacement, always liked flowmaster as I've had them on pickups and my grand national. Went with the thunder series as it was cheaper than the super 50 style plus it was very low profile. Install went well, with some very tight clearances, we spaced the rear swaybar away from the frame with some barstock steel to give us a little space. Nice tight fit with no vibrations. The exhaust is a little louder than I thought it would be but it is not ricey or tinny sounding. All in all a good flowmaster product.

      Rs464

      Year: 2008Central NH

      Helpful (3)

    • 5/5

      Installation Time: Less than 1 Hour

      December 13, 2017

      Easy Peasy...

      I got the Flowmaster quickly, and it was super easy to install. The biggest pain in the butt was taking the old stock muffler off. This system sounds great, and it feels a little more responsive. I highly recommend it.

      DavidR

      Year: 2010Submodel: Wrangler

      Helpful (2)

    • 5/5

      Installation Time: Shop Install

      Installation Cost: $100-$250

      November 25, 2017

      Different Animal

      After doing as much research as possible, I decided on this Flowmaster cat back exhaust to replace my ill-fitting Gibson side-swept cat back exhaust. Although I really did like the sound of the Gibson, this bad boy sounds pretty darn good! Makes my square peg even more of a surprise with the cold-air intake, performance throttle body, and ported manifold that I had installed previously. Don't underestimate that Wrangler that seems to be rumbling right next to you (muahahaha!!!)

      Bobzgirl

      Year: 2012Submodel: Wrangler

      Helpful (2)

    • 5/5

      Installation Time: Afternoon

      November 19, 2017

      Flowmaster American Thunder

      Hey guys, I recently bought the exhaust and installed it myself. Pretty easy if you have the right tools. I had to run to Home Depot once. The old one takes some time to get off. But the new one is well thought out and comes with everything you need to install. Highly recommend.

      AntonioD

      Year: 2016Submodel: Rubicon

      Helpful (2)

    • 4/5

      Installation Time: Less than 1 Hour

      November 07, 2017

      Nice compact design, high quality

      The exhaust has a great design, small muffler that is tucked up and above the frame rail. I have slid across rocks and the muffler was protected. The exhaust tip goes above the swaybar, its a tight fit and I bought swaybar drop brackets. It seemed to make the throttle more responsive. The sound is aggressive, it was just too loud for me. Not really any drone and it sounds mean but I sold it and went with another system. If you want one of the most aggressive sounding Jeeps out there this is the perfect exhaust.

      TomP

      Year: 2017Submodel: Rubicon

      Helpful (2)

    • 1/5

      Installation Time: Shop Install

      September 26, 2017

      Don't buy... flow master should be ashamed!

      Took the jeep to my local mechanic to install since I didn't want to try this without a lift. This guy builds dragsters and hot rods from the ground up... but this muffler has him scratching his head. Awful fit and clearly not built for a 2 door installation. At this point, I am considering having him pull it all off and sending it back for a refund. Not a typical flowmaster product and someone should take them to task for having the nerve to try and sell this as a "multi-fit"

      JimB

      Year: 2017Submodel: Wrangler

      Helpful (2)

    • 5/5

      Installation Time: Full Day

      September 15, 2017

      Sounds Great

      It has a great sound! People will definitely know your there.

      BradH

      Year: 2015Submodel: Wrangler

      Helpful (2)

    • 5/5

      Installation Time: Afternoon

      June 26, 2017

      Flowmaster Cat Back Exhaust

      Installation required grinding down a small "nailhead" on stock system at the front end of the pipe installation. Alternatively the add-on pipe needs to be cut down even for JKU in order to make it fit perfectly on back end

      GeraldY

      Year: 2016Submodel: Rubicon

      Helpful (2)

    • 5/5

      Installation Time: Afternoon

      April 05, 2017

      Flowmaster American Thunder Cat Back Exhaust

      Like others the install was fairly easy. I found mine was not lining up right and instead of cutting a little off (4 door) there is a metal index tab on the Y pipe that stops the new exhaust pipe from sliding far enough forward. Once I removed it the exhaust slide forward enough to allow everything to line up perfectly. As others stated it helps to drop the rear sway bar also. The exhaust fits like a glove once aligned properly.

      chilireds

      Year: 2015Submodel: Rubicon

      Helpful (2)

    • 5/5

      Installation Time: Afternoon

      January 12, 2018

      Great sound, quality product

      Sleek and shiny. Give your JK some serious oomph and volume. Nice upgrade

      EricS

      Year: 2010Submodel: Wrangler

      Helpful (1)

    • 1/5

      Installation Time: Less than 1 Hour

      October 23, 2017

      Horrible exhaust

      Video of the exhaust does not dipict the actual sound of the exhaust. Sounds great low RPM’s as you build it’s very loud (not a good loud) Honda Civic loud.... needless to say the stock system is currently back on the Jeep... 450.00 paper weight... I may try to splice the muffler in behind the stock resonator hoping that will help...

      Slerious

      Year: 2015Submodel: Wrangler

      Helpful (1)

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