Quiet Custom Offroad Exhaust

SmokinV10

Caught the Bug
I have been scouring several forums to get feedback on a few exhaust systems that eliminate the rear muffler on a JKUR. I have had my 2014 JKUR for several months and recently decided to move towards the EVO DTD front and rear suspension and upgrade to long arms. The two pre-packaged exhaust systems I looked at and considered buying were the Magnaflow 17143 or the Dynomax 39522. The issue I had with both was the feedback on several forums for people stating it was too loud, it droned, or it sounded raspy like a civic. The rep from Dynomax on the forum, exchanged messages with me and understood my need to keep the jeep quiet for my fiancee, and was kind enough to provide suggestions on keeping the factory resonator upstream of the 14" canister muffler offered by the 39522 system. Though I truly appreciate the candor from the vendor, the more I thought about it, the more I felt that it was a shame to buy an exhaust system only to butcher it. I decided to take it to a custom exhaust shop to have a custom stainless system installed.

When I got to the shop we discussed utilizing a 6" round 14" long 2.5" inlet/outlet canister muffler with the factory resonator in place. I knew that this would scavange more exhaust energy than the canister muffler on its own. What I ended up going with is a 24" long 5x8 oval 12286 muffler where the factory resonator resides and dumping by the skid of the rear drivers side control arm (factory control arm skid location). All pipes were stainless and I was able to keep the muffler tucked up higher than the factory resonator.

The end result (dont ask for sound clips because Im honestly too lazy to take videos) is a VERY quiet exhaust system. Lets put this in context. Its louder than stock, but not much. You can definitely hear it when your foot is on the gas and you are accellerating but its not bad AT ALL. I would be surprised if anyones wives or girlfriends complained. At 60mph (on 37" tires and 4:88 gears) it doesnt drone at all. At 70mph you can hear the exhaust, but the wind noise from my light bar and the tire noise from the toyo open country's FAR exceeds the noise of the exhaust. At 80mph ~3000rpm), the exhaust noise is there but everything else is noisier. At 85mph it quiets down to a nearly imperceptable hum again.

Basically I think the longer oval muffler solved the problem many here are looking for. Unfortunately its not a kit, but the result is a clean looking full stainless system that cost me less than $300 installed. (actually $307 with tax).

Pics below:
image1.jpeg

image2.jpeg

image3.jpeg


image5.jpeg

image6.jpeg

image7.jpeg

image8.jpeg
 
Also I have the dynomax exhaust you stated and barley hear it at red lights. I does a nice semi loud growl when start up but my neighbors don't get disturbed by it and get semi loud when you first start Rollin but fades to nice low hum when you get up to speeds


Sent via carrier pigeon
 
Custom work is great as I could never do any of that. Being said, I'd find a skid for that if you plan to wheel. Seems to be in an open area subject to rocks and things and hangs down below your frame rails.

Just wouldn't want you to smash that thing up your first trip out. :thumb:
 
Custom work is great as I could never do any of that. Being said, I'd find a skid for that if you plan to wheel. Seems to be in an open area subject to rocks and things and hangs down below your frame rails.

Just wouldn't want you to smash that thing up your first trip out. :thumb:

A skid for what? It's a muffler it can get dented in. Look at mine sometime.
 
Also I have the dynomax exhaust you stated and barley hear it at red lights. I does a nice semi loud growl when start up but my neighbors don't get disturbed by it and get semi loud when you first start Rollin but fades to nice low hum when you get up to speeds


Sent via carrier pigeon

I have a Dynomax in the same location as the OP put his. I have bashed it a number of times and the last hit that it took, it pushed it up to the frame cross member, so there is slight vibration now at certain points in the RPM range. Not terrible but its there. I also don't have carpet in my jeep, interior tub is Rhino Lined and I get extra heat in the footwell of the driver side back seat.

I plan to add some type of flexible heat shield to the bottom of the tub but will need to remove the muffler to install it.
 
True, but seems like the EVO comp exhaust is tucked up a bit more and the muffler is much smaller. But I get what you're saying as well.

the EVO exhaust is smaller in width but has a 6" diameter I believe. This is tucked up as high as it can go and is a 5x8 oval. from a vertical diameter perspective, this muffler is actually 1" shorter in height. I am GUESSING but I feel its safe to assume that my system still protrudes less than the EVO by about a half an inch. It is literally tucked up as high as I can without causing it to rattle against the frame/tub/floorboard. The caveat to that statement is that it is a longer muffler (by 10 inches) than the unit used in the EVO system. Tradeoff for noise. Pick your poison. I am ok with a $180 muffler taking a few dings and doinks. Punch a hole and it wont kill me to buy a new one. I still feel that I found a good compromise with having the larger muffler in the back or having the noisier "other" systems where this custom system is located. I'll have to take a picture from a position where the camera is not located below the car. It does protrude the frame rails but not significantly.

From a heat standpoint. I have driven an hour at 80+ mph with the system and I dont have any heat related issues when I put my hand against the floorboard after getting to my destination. Maybe the air passing over the muffler at those speeds helps. The key is that the engine is under load the whole time at those speeds so it is also likely that the muffler gets pretty warm. I am sure it will be worse on the trails. In the case that it does become an issue, it wouldnt be hard to cut a piece of inconel heat shield from race car parts I have and secure it around the muffler. Another option is to unbolt the system and have it ceramic coated. Or.... http://www.summitracing.com/parts/hsp-721202/overview/

tons of options
 
Last edited:
the EVO exhaust is smaller in width but has a 6" diameter I believe. This is tucked up as high as it can go and is a 5x8 oval. from a vertical diameter perspective, this muffler is actually 1" shorter in height. I am GUESSING but I feel its safe to assume that my system still protrudes less than the EVO by about a half an inch. It is literally tucked up as high as I can without causing it to rattle against the frame/tub/floorboard. The caveat to that statement is that it is a longer muffler (by 10 inches) than the unit used in the EVO system. Tradeoff for noise. Pick your poison. I am ok with a $180 muffler taking a few dings and doinks. Punch a hole and it wont kill me to buy a new one. I still feel that I found a good compromise with having the larger muffler in the back or having the noisier "other" systems where this custom system is located. I'll have to take a picture from a position where the camera is not located below the car. It does protrude the frame rails but not significantly.

From a heat standpoint. I have driven an hour at 80+ mph with the system and I dont have any heat related issues when I put my hand against the floorboard after getting to my destination. Maybe the air passing over the muffler at those speeds helps. The key is that the engine is under load the whole time at those speeds so it is also likely that the muffler gets pretty warm. I am sure it will be worse on the trails. In the case that it does become an issue, it wouldnt be hard to cut a piece of inconel heat shield from race car parts I have and secure it around the muffler. Another option is to unbolt the system and have it ceramic coated. Or.... http://www.summitracing.com/parts/hsp-721202/overview/

tons of options

got a part number or brand by chance of the muffler your installer used? Sounds smaller but maybe a little longer than my Dynomax but I would need to measure.
 
Looks great.

I also wanted to get rid of the stock muffler out back but did not want it to be too loud. I did something similar with a Dynomax Super Turbo where the stock resonator was followed by a six inch round can similar to the Dynomax Evolution.

Tight fit but very quiet (stock quiet) and sits tucked up above the frame rails for the most part except for the back 2-3 inches of the 6 inch can where the frame rises for the rear axle.

A friend owns an exhaust shop so was lucky to play around with a few options. A 4" can that Magnaflow makes fits better/higher but it resonated and droned too much for me so we went back to the 6". I figure if I bounce off of a rock it'll just be self cleared for the next time.
 
Love to see pics of this setup.
ALso a good shop will have a few options of mufflers that can be slipped on to get you an idea of how it will sound. :beer:

Looks great.

I also wanted to get rid of the stock muffler out back but did not want it to be too loud. I did something similar with a Dynomax Super Turbo where the stock resonator was followed by a six inch round can similar to the Dynomax Evolution.

Tight fit but very quiet (stock quiet) and sits tucked up above the frame rails for the most part except for the back 2-3 inches of the 6 inch can where the frame rises for the rear axle.

A friend owns an exhaust shop so was lucky to play around with a few options. A 4" can that Magnaflow makes fits better/higher but it resonated and droned too much for me so we went back to the 6". I figure if I bounce off of a rock it'll just be self cleared for the next time.
 
Love to see pics of this setup.

Hey Matt, I actually did the super turbo on your suggestion! Sorry for the crappy pics, best I could do in the parking lot at work before folks started wondering what the hell the guy in the suit was doing crawling under the JK, :).

Also, apologize for the brand of the 6" can, buddies shop carries your alls oval mufflers but not the rounds, bugs the hell out of my OCD'ness but I'm sure yours would fit the same.

Sits tucked up just above the frame rails, can't see it at all from the side looking at it on the level until you get to the very back of the round can, I'll probably beat the hell out of it there "mall curb" and you can see it sits about a half inch or so lower than stock evap skid looking at the 3rd picture.

ImageUploadedByWAYALIFE1398983577.304827.jpg

You can see the tail of the 6" here between the lower control arm and where the frame turns north.

ImageUploadedByWAYALIFE1398983595.390791.jpg

ImageUploadedByWAYALIFE1398983712.184298.jpg

Looking towards the front, super turbo fits up nice and tight just bwt the two cross members that go over the trans/driveshaft.

ImageUploadedByWAYALIFE1398983738.258305.jpg

Sound is very close to stock, no drone, etc. so it's nice and boring just how I wanted it, after it gets beat on I'll just ditch it for the Evolution like all the other kids, :)

Apologies to the OP for the hijack, I was in the same boat looking for quieter options too.
 
Last edited:
Ha! Very nice!! Is the other round a Magnaflow? It's OK, it's going to happen. :)

Hey Matt, I actually did the super turbo on your suggestion! Sorry for the crappy pics, best I could do in the parking lot at work before folks started wondering what the hell the guy in the suit was doing crawling under the JK, :).

Also, apologize for the brand of the 6" can, buddies shop carries your alls oval mufflers but not the rounds, bugs the hell out of my OCD'ness but I'm sure yours would fit the same.

Sits tucked up just above the frame rails, can't see it at all from the side looking at it on the level until you get to the very back of the round can, I'll probably beat the hell out of it there "mall curb" and you can see it sits about a half inch or so lower than stock evap skid looking at the 3rd picture.

View attachment 81292

You can see the tail of the 6" here between the lower control arm and where the frame turns north.

View attachment 81293

View attachment 81294

Looking towards the front, super turbo fits up nice and tight just bwt the two cross members that go over the trans/driveshaft.

View attachment 81296

Sound is very close to stock, no drone, etc. so it's nice and boring just how I wanted it, after it gets beat on I'll just ditch it for the Evolution like all the other kids, :)
 
Make it happen. Get the welds and bends perfect and I may even swap what I just built for a shiny new polished setup. Looks like the other ops setup sits about 1/2" higher than mine.
 
Last edited:
There was actually talk about a setup like this a few weeks ago out in Moab, we move slow ( long story short "my" engineer does a lot on OE side too) but this type of threads get the bosses' attention. :)


Make it happen. Get the welds and bends perfect and I may even swap what I just built for a shiny new polished setup.
 
Ha! Very nice!! Is the other round a Magnaflow? It's OK, it's going to happen. :)

...and that, sports fans, is why DynoMax rocks. It speaks volumes about a manufacturer's confidence in its products that the reps take the time to help people figure out solutions (even when those solutions may not involve the manufacturer's packaged products.)

Good form DynoMax, good form. :clap2:
 
There was actually talk about a setup like this a few weeks ago out in Moab, we move slow ( long story short "my" engineer does a lot on OE side too) but this type of threads get the bosses' attention. :)

Add me to one more potential customer for a polished project like this.
 
Awesome! This is exactly what I have been looking for myself. I want a fairly high tucked, stock quiet system that will work with the EVO Lever that I am saving for...

My Jeep tends to be my daily driver, as I prefer to drive it over our other vehicles. But, with my carpet long gone, soft top only, and 12.5 Trail Grapplers I really don't want more noise.
 
Top Bottom