One of the most common purchases we make as Jeepers is an after-cat exhaust kit. Whether our old one rusted off, we are just looking for some more power, or we just want the Jeep to sound better, an after-cat exhaust system takes care of all those needs.
Over the years we have been through a bunch of after-cat kits and the one thing that we've run into on more than one occasion is that the kit sounds nothing like we thought it would. Some kits have even been so loud or resonated so much that we swapped mufflers just to quiet down our new exhaust system. So, one of the things we wanted to do with this shootout is to bring you some feedback on what the kit sounded like. Since you can't hear an exhaust kit on paper, we simply rated it here. Then we shot video both inside and outside the Jeep so that you can get a good idea of what it sounds like just by going to jpmagazine.com
The other thing that no other magazine would attempt to bring you is a report on just how easily or difficult eleven after-cat kits install. Any other magazine would have a shop do all the work for them while they just shot pictures. Not us; not only did we install and remove all of these kits ourselves, we did it in our driveway on our backs with hand tools much like you would do at home.
The test mule for this was our '01 Wrangler with a six-cylinder, manual transmission, 4 -inch short arm Currie Enterprises lift kit, 35-inch tires and a 1-inch body lift. At that elevation, we didn't run into any driveway related interference, but at 2 or 3 inches of lift we would have. As it was, we didn't have to jack up the Jeep and use jack stands to then lower the axle, we were able to snake all of the mandrel bent tailpipes around the axle, body, frame, and suspension components fairly easily.
Every kit we originally lined up used a free-flowing muffler and 2 1/2-inch mandrel-bent tubing to exhaust the gasses out the back and touted similar horsepower gains. We don't deny that there is power to be had in an after-cat kit, but buying one over the next because of power gains is ludicrous. With so many similarities any dyno numbers we got could have easily been attributed to the variance in the dyno itself. The single digit differences between kits that we expected to see wasn't nearly as important to us as what it sounded like on a six-cylinder Jeep or how hard it was to install.
After bolting each kit on, we taped a microphone to the rear bumper and drove around so you could hear what it sounds like outside the Jeep, and then shot video from inside the Jeep so you could hear what you'd hear driving it. Since our '01 is a soft top Jeep, if you have a hardtop your interior noise level might be different.
Once we got done driving around, we sat down and took notes on how easy each kit was to install, how complete and easy to follow the instructions were, how the kit cleared under-body components, and how complete the kits themselves were (did they include all bolts, nuts, clamps, and hangers to install, or did we have to run to the parts store). After taking notes on all of them, we rated them on a scale of 1 to 10 with a 10 being the Megan Fox end of the scale and a 1 being the Roseanne Barr end of the scale for installation and completeness. For volume 10 is the loudest we encountered and 1 is the quietest.
While we did rate individual aspects of each kit, we didn't give you a winner. All the kits we tested are high-quality, and in fact a one or two point difference between one or the other is very minimal. Besides, we like to think that our readers are smart enough to draw their own conclusions on what is important to them in an after-cat kit. So, check out our brief summaries, our pros and cons, and how the kit rates, and then go watch the videos on jpmagazine.com to decide what your next Wrangler after-cat kit should be.
4WD Hardware Aluminized
Pros: Low price point Very complete kit (even included parts for Unlimited)
Cons: Tight fit around upper control arm mount with muffler flat Rear hanger requires unbolting for installation
Installation: 8
Fitment: 6
Completeness: 10
Volume: 6
Sound Notes: Good middle of road sound, just loud enough to know it's there with no annoying resonance occurring anywhere in the RPM range.
4WD Hardware Stainless Steel
Pros: Low price point for stainless steel Cool chambered stainless muffler
Cons: Fits tight around rear shock Rear hanger requires unbolting for installation
Installation: 8
Fitment: 9
Completeness: 10
Volume: 8
Sound Notes: While louder than many, it wasn't annoying and didn't vibrate us out of the Jeep. Reminiscent of a Flowmaster with a tailpipe
Banks Monster Exhaust
Pros: Great installation High chromium stainless muffler should combat rust
Cons: Tailpipe really close to both track bar and shock Discolors after driving a while
Installation: 10
Fitment: 9
Completeness: 10
Volume: 9
Sound Notes: Can be heard even on the freeway over soft top and mud tires. However, it's a pleasant sound and surprisingly not tiring or droning on long trips.
Borla Cat-Back
Pros: Cool looking trademark rectangular tip Extra tip and nuts included
Cons: Trademark tip doesn't clear ARB bumper Really tight tailpipe fit (within -inch of control arm bolt)
Installation: 8
Fitment: 8
Completeness: 10
Volume: 5
Sound Notes: Good tone. Somewhat noticeable around town but not so on the freeway, only at higher RPMs.
Cherry Bomb
Pros: Heavy-duty, bomb-proof muffler Lots of installation adjustability
Cons: Lots of little parts 2 1/4-inch tailpipe
Installation: 7
Fitment: 5
Completeness: 10
Volume: 5
Sound Notes: Way quieter than we expected from Cherry Bomb. We expected too loud to handle easily and were pleasantly surprised by a deep, mellow tone.
Dynomax Super Turbo
Pros: Good instructions Quiet and unobtrusive tone
Cons: Slight contact with shock no matter what Almost stock sound
Installation: 9
Fitment: 8
Completeness: 10
Volume: 2
Sound Notes: Quiet, almost stock like. A bit louder at idle, and under 10mph, but after that it is inaudible over road, wind, and tire noise.
Gibson
Pros: Heavy-duty, bashable muffler Quite loud at idle and on surface streets but fades into background on freeway
Cons: Tailpipe very close to track bar, contact possible at full stuff Tailpipe too long, cutting necessary
Installation: 9
Fitment: 7
Completeness: 10
Volume: 8
Sound Notes: Louder than expected but easy to live with on the freeway.
Magnaflow Performance System
Pros: Good clearance everywhere Easiest install of the bunch
Cons: Missing nuts to bolt muffler to cat Heavy muffler (watch your head!)
Installation: 10
Fitment: 10
Completeness: 8
Volume: 6
Sound Notes: Just noticeable at every RPM and speed. Nice sound inside Jeep, sounds like a Jeep possessed outside.
Pacesetter Tfx Exhaust
Pros: Easy install Few loose parts
Cons: Too long, cutting needed Silver paint comes off on skin during install
Installation: 10
Fitment: 6
Completeness: 10
Volume: 4
Sound Notes: Just a bit louder than the Dynomax kit but still with a deep tone.
Turbo City
Pros: Hangars not welded to tailpipe (more adjustability) Tailpipe cleared well
Cons: Many loose parts Muffler didn't align 100% with cat
Installation: 6
Fitment: 6
Completeness: 10
Volume: 4
Sound Notes: Uses a different Magnaflow muffler than the Magnaflow kit, but ends up with a much mellower tone that is also fairly deep.
Volant Performance Exhaust
Pros: High quality parts TIG welded together
Cons: Side exit in close proximity to rear tire Close to track bar
Installation: 9
Fitment: 9
Completeness: 10
Volume: 6
Sound Notes: Noticeably louder outside than inside. A good Saturday night cruising special that lets people know you are there without wearing you out.
Flowmaster
Many Jeepers recognize the sound of a Flowmaster-shod Jeep. The reason we didn't include Flowmaster officially in the testing is that as of this writing, the company doesn't make an after-cat exhaust kit for an '01 Wrangler. We got a hold of a comparable center inlet, offset outlet muffler and used it both with a custom tailpipe and with a turn down in front of the rear axle so that you could compare the other kits on our website to something you likely have already heard and make a more informed decision with this baseline. Check out jpmagazine.com for the Flowmaster sound
Stock
The stock tailpipe is 1 -inch tube and not mandrel bent; check out how much more free-flowing the aftermarket pipes look. If that wasn't enough, the muffler is about 10 feet long and as restricting as anything we've seen. That said, we shot video with the stock '01 exhaust kit as well for another basis of comparison. For rating comparisson, the volume of the stock exhaust is 1, but check out the jpmagazine.com website for all your cat back comparison videos.