Back when Moby was still running a 3.8L V8 motor, we ran a Dynomax Ultra Flo Evolution Competition exhaust system as it fit well with our EVO Lever System and loved the way it sounded. There were times where people would literally ask us if we had a V8 under the hood as it had a really nice throaty purr to it but no so loud that it was bad at highway speeds. Needless to say, when it came time to install a new exhaust system on Rubicat, it's what we decided to run again. Unfortunately, what we soon discovered is that with a newer 2012-up JK Wrangler, the sound of this exhaust system was a bit "different" to say the least and in spite of the fact that it was the exact same kit. The problem was, the newer 3.6L motor has a less than pleasant sound all on it's own and one that Chrysler used a resonator to help mellow out before reaching the muffler. And, the problem for us was that we needed to remove the resonator in order to run the Ultra Flo Evolution Competition exhaust system. While the fitment was good and the sound wasn't too bad, we found there was a pretty heavy drone while running at highway speeds. Around town or on the trail, it wasn't even noticeable or at least not to us but on really long drives, like heading out to Moab, it could become mind numbing.
After Dynomax announced the release of their all new QuietCrawler Performance Exhaust System earlier this year and noted that it was "specifically designed to provide high clearance for rockcrawling and quiet acoustics for everyday driving in your 3.6L Jeep Wrangler 4 door", we knew it was something we had to try. The only problem was that the kit was really made more for a JK Wrangler that has a tailpipe that goes all the way to the back and so we weren't sure if we could get it to work with our EVO Lever. Fortunately, Matt over at Dynomax was able to help us figure things out and after ordering up a kit, I was able to get it installed over the weekend. Here are some shots of what it looks like installed as well as a few that shows what I had to do to make it work.
Racking Rubicat up and getting ready to swap our exhaust system.
Here's a shot of the QuietCrawler Performance Exhaust System or at least, the pieces that I would be needing.
Fortunately, I already had an exhaust hanger from our old Evolution Competition kit that gets mounted to the forward bolts of the EVAP skid plate and I was able to reuse it. However, in order to use it, I had to cut the hanger and re-weld it so that it pointed inward.
Using a piece of old 2.5" exhaust pipe I had laying around, I cut it down short enough so that it could be used as a coupler between the Ultra Flo muffler and the Race Bullet. I then secured everything in place with a wide exhaust clamp. I also cannibalized an old exhaust hanger I had on an old tail pipe and welded it to a standard exhaust clamp so that it could be connected to the hanger mounted to the EVAP skid plate.
Here are a few shots of what everything looked like when all was said and done. As you will see, I installed a downturn on the Race Bullet so that the exhaust would dump in front of the rear axle.
Here's a couple of shots from the back.
Finally, here you can see how none the exhaust system hangs below the frame rail. Well, maybe just the very back lip of the muffler but barely even that.
What we really like about this new QuietCrawler Performance Exhaust System is that it's really flat and sits about in line with the frame rail if not a bit above it and that's a HUGE plus for us. So far, the location of the exhaust dump doesn't seem to be an issue and it's pretty much blowing clear of everything. Of course, what I'm sure most of you are wanting to know is how it sounds and what I can tell you is this. After firing up Rubicat and letting her idle, you could hardly tell the motor was on. At least, by comparison to what we had, it sounded a lot like stock. What's cool is that under a load like taking off hard off the line, it has a really nice deep throaty sound a lot like what our old Evolution Competition System sounded like on Moby with his 3.8L motor. That was a surprise and one that we really like. The best part is, at highway speeds, the exhaust is now significantly quieter now and even with the Nitto Mud Grapplers we're running (which are now way louder than the exhaust), we can now carry on a normal conversation without yelling at each other. Granted, it's still louder than factory but I suspect that it would be quieter if we were dumping all the way at the back of the Jeep. But, for our purposes, we really like the beefier sound and was really just wanting to kill the drone which I think this kit has.
Below is a short video that'll help illustrate what the Dynomax QuietCrawler Performance Exhaust System sounds like both inside and out of the Jeep and under different conditions. Please take note that we are running BIG 40x15.50 Nitto Mud Grapplers and the humming sound you hear is coming from them.
Please let me know if you have any questions
After Dynomax announced the release of their all new QuietCrawler Performance Exhaust System earlier this year and noted that it was "specifically designed to provide high clearance for rockcrawling and quiet acoustics for everyday driving in your 3.6L Jeep Wrangler 4 door", we knew it was something we had to try. The only problem was that the kit was really made more for a JK Wrangler that has a tailpipe that goes all the way to the back and so we weren't sure if we could get it to work with our EVO Lever. Fortunately, Matt over at Dynomax was able to help us figure things out and after ordering up a kit, I was able to get it installed over the weekend. Here are some shots of what it looks like installed as well as a few that shows what I had to do to make it work.
Racking Rubicat up and getting ready to swap our exhaust system.
Here's a shot of the QuietCrawler Performance Exhaust System or at least, the pieces that I would be needing.
Fortunately, I already had an exhaust hanger from our old Evolution Competition kit that gets mounted to the forward bolts of the EVAP skid plate and I was able to reuse it. However, in order to use it, I had to cut the hanger and re-weld it so that it pointed inward.
Using a piece of old 2.5" exhaust pipe I had laying around, I cut it down short enough so that it could be used as a coupler between the Ultra Flo muffler and the Race Bullet. I then secured everything in place with a wide exhaust clamp. I also cannibalized an old exhaust hanger I had on an old tail pipe and welded it to a standard exhaust clamp so that it could be connected to the hanger mounted to the EVAP skid plate.
Here are a few shots of what everything looked like when all was said and done. As you will see, I installed a downturn on the Race Bullet so that the exhaust would dump in front of the rear axle.
Here's a couple of shots from the back.
Finally, here you can see how none the exhaust system hangs below the frame rail. Well, maybe just the very back lip of the muffler but barely even that.
What we really like about this new QuietCrawler Performance Exhaust System is that it's really flat and sits about in line with the frame rail if not a bit above it and that's a HUGE plus for us. So far, the location of the exhaust dump doesn't seem to be an issue and it's pretty much blowing clear of everything. Of course, what I'm sure most of you are wanting to know is how it sounds and what I can tell you is this. After firing up Rubicat and letting her idle, you could hardly tell the motor was on. At least, by comparison to what we had, it sounded a lot like stock. What's cool is that under a load like taking off hard off the line, it has a really nice deep throaty sound a lot like what our old Evolution Competition System sounded like on Moby with his 3.8L motor. That was a surprise and one that we really like. The best part is, at highway speeds, the exhaust is now significantly quieter now and even with the Nitto Mud Grapplers we're running (which are now way louder than the exhaust), we can now carry on a normal conversation without yelling at each other. Granted, it's still louder than factory but I suspect that it would be quieter if we were dumping all the way at the back of the Jeep. But, for our purposes, we really like the beefier sound and was really just wanting to kill the drone which I think this kit has.
Below is a short video that'll help illustrate what the Dynomax QuietCrawler Performance Exhaust System sounds like both inside and out of the Jeep and under different conditions. Please take note that we are running BIG 40x15.50 Nitto Mud Grapplers and the humming sound you hear is coming from them.
Please let me know if you have any questions
