Flowmaster Cat-Back Exhaust System 2-1/2" American Thunder Single Exit Stainless Steel Jeep Wrangler JK 2007-2018



  • Moderate Exhaust Tone
  • Stainless Steel Construction
  • Made In The USA
  • Includes Necessary Hardware
MSRP $547.00
You save 10%

Flowmaster 2-1/2" Stainless Steel Single Exit American Thunder Cat-Back Exhaust System for 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017 and 2018 Jeep JK Wranglers.

This 2-1/2" Stainless Steel Single Exit American Thunder Cat-Back Exhaust System from Flowmaster is perfect for off-roaders who are looking for maximum performance and ground clearance for their 2007-2018 Jeep Wrangler JK. Plus, it adds an improved and aggressive exhaust note to the Jeep JK!

Features and Benefits of the Flowmaster 2-1/2" Stainless Steel Single Exit American Thunder Cat-Back Exhaust System (817674):
- High-grade stainless steel construction
- 3-3/4" tip length / 3" tip diameter
- Mandrel bent tubing
- Moderate to aggressive exhaust sound
- Provides maximum off-road clearance
- Comes with necessary parts and hardware
- Proudly made in the USA

This 2-1/2" exhaust system features a 409S stainless steel mandrel bent tailpipe with a 3" polished stainless steel tip. It fits both 2 and 4-door JK models with 3.6L and 3.8L V6 engines. This system replaces the factory transverse muffler and relocates the Super HP-2 muffler behind the factory catalytic converter, providing a moderate to aggressive sound level.

This relocation allows for better ground clearance when driving off-road. Because the tailpipe is tucked up so high, an aftermarket metal bumper is recommended. The exhaust system is manufactured in the USA. It is designed for an easy fit and includes all necessary parts and hardware for installation.

Tech Tip: For installation on 2-door models, a 20-1/2" section will need to be cut from the long end of the over axle pipe.

Flowmaster is a manufacturer of a wide variety of premium exhaust components, from full exhaust systems and exhaust kits, to mufflers and accessories. Flowmaster is widely known for its distinctive 'Flowmaster sound,' which is available in mild, moderate and aggressive tones.

Order Flowmaster's 817674 2-1/2" Stainless Steel Single Exit American Thunder Cat-Back Exhaust System for your 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017 or 2018 Jeep JK Wrangler from CJ Pony Parts today!

California Residents: Proposition 65 Warning

Installation Difficulty


Novice skill is required for this installation.

Installation Videos

Video Transcript

Freddy: We recently just installed a Flowmaster Outlaw axle-back exhaust on our JK Wrangler, but today we're going to take it a step further by installing this Flowmaster American Thunder catback. I have special guest Jeremy from Flowmaster. Jeremy, what can you tell us about this catback?

Jeremy: Hey Freddy, thanks for having me out here. This catback is an excellent system for somebody looking to upgrade the sound and their performance on their JK. The really cool thing about this is it tucks up really tight to the body of the vehicle. If you're out doing some hardcore off-roading, you don't have to worry about beating your exhaust system to death.

Freddy: Yeah.

Jeremy: It tucks up nice. It's got a good aggressive sound to it. It's not aggressive as some of our other kits, if you're familiar with the Outlaw system. It's got a good moderate tone to it. You can definitely that it's an upgraded exhaust. You're going to get better flow with the mandrel bends. This is all two and a half inch pipe. We've got our HP2 exhaust muffler here with laminar flow design, so it's really kind of a throaty, more of a bass tone, as opposed to some of our exhausts. It's a great performance upgrade. Like I said, up tight so you don't have to worry about bashing it when you're off road.

Freddy: Jeremy, what will this exhaust fit?

Jeremy: This fits all the Jeep JKs from '07 to 2017, the three-six and the three-eight liter motors, as well as the two and the four door Jeeps.

Freddy: Okay.

Jeremy: It's a good system.

Freddy: Awesome. Let's get to the installation. For this installation, you'll need a lift or a jack and jack stance, and also another set of hands, a 3/8 ratchet, 16 millimeter socket, half inch ratchet, 15 millimeter socket, 18 millimeter socket, and an exhaust hanger and removal tool. We have the Jeep up in the air. Jeremy, what's the first thing we should do?

Jeremy: We're going to start by removing basically the stock axle back system, that way we can kind of wiggle the rest of it. We're going to start here and work our way forward.

Freddy: All right. The first thing we're going to do is remove this clamp by the removing the 15 millimeter nut. We're going to remove the rubber hanger now. We're going to remove it from the chassis bracket instead of the muffler bracket.

Yes. Then remove the other rubber hanger from the muffler. Then, twist the muffler and pull it off. Loosen the nut with a 15 millimeter wrench. This clamp can be really tricky to loosen. You can't really get a socket and ratchet on there; got to the use the wrench and apply a lot of force. The clamp can't be removed because it's welded to the pipe, but once you loosen it, remove all the rubber hangers. Remove the final hanger.

You're probably going to run into some clearance issues when trying to remove the factory system. As you can see right here, the resonator is hitting the evap canister mount. Can't really do anything about it, so what we're going to do, the easiest option is to drop this skid plate right here. It's only four bolts. You don't need to completely remove these two, just loosen them. Slide the exhaust back, and then bring it forward.

With the factory system removed, the first thing we're going to do is put this clamp over the Y plate. With the clamp in place, we're going to install the front pipe. Now, if your Jeep is 2007 to 2011, you're going to put the rubber hanger on the front bracket. If you have a '12 to '17, you're going to utilize the further downstream bracket. Whichever one you don't use, if you want, you can cut it off.

Now we're going to install the HP2 muffler. This is directional. You can see the arrow right here pointing to the Flowmaster logo. This needs to go pointing towards the tail pipe. We're going to put the clamp over the muffler and we'll put it over the front pipe.

Jeremy: Okay, so now this kit is designed for the two and the four door. Obviously we got different length wheel bases. If you got a two door JK, you want to take out about 20 and a half inches from the front of the pipe that goes to the muffler, cut that off there, you'll be good to go.

Freddy: With the muffler in place, you can now install the over axle pipe over the rear sway bar. Bend the heat shield out of the way to make some clearance. Put a clamp over the over axle pipe. Undo the sway bar brackets to give you more room. Install the tail pipe.

Once you get everything in place, you can install these hanger retainer switch, keep the rubber hangers in place. Once you get everything in place, you can tighten all the clamps, starting from the front, then work your way back. Reinstall this skid plate with the four bolts, then your installation's finished.

All right, let's hear it. Our Flowmaster American Thunder catback is also installed. It sounds really good.

Jeremy: As you can see, you can't see it; and that is the point. It's made to be tucked up right underneath, close to the body so if you're out on the trail, you're not going to bash it up with rocks and everything else.

Freddy: Yup. This exhaust, along with other Flowmaster exhausts, can be found for your JK Wrangler at CJPonyParts.com.

Vehicle Fitment

This product will fit the following Wrangler years:

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