Flowmaster 817674 American Thunder Cat-back Exhaust System

Installed on my 2009 Wrangler JKU with the 3.8 and it sounds amazing! I have always been against putting an exhaust on a v6 but this was worth it. you will have clearance issues on your rear sway bar and your frame. you can either buy the drop brackets or add some washers in there to move the sway bar down just a hair. you don't have to do either one really but you may get a rattle every now and then. I ran mine without moving the sway bar a few days but then went back and slid some washers in between the bracket and the frame just to keep that occasional rattle from coming about. seems like it only happened when someone was checking out the jeep lol. Very easy install. The Uninstall of the old exhaust was the hardest part.... mainly getting the hangers out to drop the old exhaust... I sprayed some PB Blaster on the rubbers to provide a little lube... made the job much easier but was still a pain. my old pipes were seemingly welded together by the heat that passes through them lol so some KROIL and a little elbow grease and they all separated in the end. install probably took about 2 hrs working on the ground with no jacks necessary and a couple of buddies for a few good laughs Installed with the Rugged Ridge XHD Snorkel, SuperChips Flashpaq 3872, AFE Silver Bullet Throttle Body Spacer, and Rugged Ridge High flow air filter. Very happy with overall results. Extremely happy with my new exhaust.no drone. I have floor plugs out and it isn't bad at all! has the sound of a jeep without a muffler, just not as loud. very sexy!

Pro's:Install was easy IF you have done something like this before. Pulled in garage at 1, pulled back out at 4.Sounds great. Deepest sounding exhaust I have heard for the pentastar.Tucks way up in the frame, perfect for clearance.Con's:Install would be difficult IF you have never done one or don't have proper tools. I had to cut the long pipe a couple of inches on both ends to fit it perfectly but the result was worth it.You HAVE to take the five minutes to remove the transfer case skid pan and rear sway bar. Easy with the right tools, little more difficult with hand tools but it needs to be done.Tucks so far up in there that it is a picky job to get everything just right. For my install the muffler sits about an 1/8" away from the rear most cross member on my Unlimited. Amazingly after driving about 150 miles it has not touched.While this is the deepest toned exhaust I have heard for a pentastar motor it still aint no Hemi and no exhaust is going to make it sound that way.Good luck.

I installed this exhaust on a 2 door 2013 Rubicon with 36k miles (a little rust) and a Teraflex 2.5" lift. I did it alone on the garage floor with hand tools, angle grinder, and a dremel. Removing the old exhaust takes the most time. The rubber exhaust hanger are a pain but can be removed with a pry bar. I had no luck removing the bolts on the exhaust clamps so I just cut the clamps with a dremel tool cut-off wheel. I loosened the skid plate near the y pipe and drooped it down a little to squeeze out the front portion of the old exhaust. Then you just wrestle the muffler and forward portion out by twisting back n forth. Installation was easier. I cut the long straight pipe a little less than recommended at first but found that their recommended cut length was correct. when routing the rear portion over the swaybar I found that it was nearly resting on the sway bar no matter how I adjusted it. I tightened everything down and started it up. It didn't rattle against the swaybar under most conditions but sometimes did. I considered putting washers under the sway bar mount to create space but I instead ordered some rear sway bar drop spacers from Metalcloak that are intended for a different application but worked perfectly to create plenty of space in this application. I don't believe the spacers have any adverse effects on the rear suspension geometry with the Teraflex 2.5" coil lift (with longer sway bar end links). I don't think it would be a problem with any set-up really though. Flowmaster should include similar spacers in this kit. That is why I subtracted a star. The sound is subjective but I would say that it is louder than the popular magnaflow axle back kit, but not really loud at all idling. It has a very deep idle sound for a V6. It get's pretty loud under heavy acceleration. It can produce subtle crackles and pops when letting off the gas even in an automatic. The sound does change a bit after about 100 miles. Seems a little quieter at idle now. It can drone slightly at a very specific rpm if purposely kept there but I doubt most would notice it. I don't consider the sound ricer at all. It sounds more like an old truck than ricer. The way it tucks up into the Jeep is really good for off-road. I can't imagine it being possible to hang it up on anything. When you're lifted and have some nice components underneath it's also kinda nice to get that ugly, stock, school bus muffler, out of the view. I would recommend this kit if you've got the tools to cut and fit this on a 2 door and you're willing to buy the sway bar drop spacers.

Nice system. Glad to get rid of the Jeep factory steel suit case rear muffler. After you install it head to the muffler shop to have the joints welded. Clamps are good but system will leak if that’s all you go with. Good job on the bend over the rear axel. Sound is definitely moderate with a little throaty rumble. I’m happy with the end result. The hardest part is removing the old system. Took about 2 hours from start to finish.

Muy decepcionado y molesto por la transacción. No puedo juzgar el producto ya que la entrega fue incompleta. Le faltaba el silenciador (muffler 409S HP2) componente clave, también el kit de fijación y cualquier instrucción de instalación. No hay correo electrónico o teléfono para contactar y quejarse. Engañado.

At first I was a little shocked because the exhaust sounded unexpectedly loud. But I soon found that after a few days the sound seemed more subtle unless you push the car full throttle to 3000 RPM where it has a very notable race sound. Then again above that the sound is really not that different from stock while tire and engine noise take over. In daily driving and low RPMs there is a nice deep tone that still allows for music and conversation. It helps to drive a manual to have full control. Conclusion: break it in for a few days and you will get noticed without embarrassing yourself.Application:Off-roader: Yes - for off-road clearance you will not find a better exhaust. This one completely disappears under the car.Modified/accessorized Jeep: Yes - just remember it's called "American Thunder" for a reason. People will know it's there.Soccer mom and daily driver: Probably not.Install: Despite what various videos claim on YouTube you will most likely need help unless you are a mechanic. We needed a propane flame, angle grinder, and hammer just to get the stock system off. The Flowmaster pipes run really tight past various corners which may require adjustment if vibrations occur. But for me it was all worth it.

Just the right amount of growl I was looking for. Not too deep and not too loud. Perfect

Louder than I thought it would be. Make sure you are ok with noise. The videos I watched on youtube didn't quite do it justice for the amount of noise this thing creates. If I could do it all over again, I'd look for a quieter system.I do however love the fit. It tucks up under the bumper just as I wanted.Sound is a nuisance only while city and highway driving. On the trails it sounds cool.

Perfect!