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Dudes. I have a 2018 JKU Sahara. 40k miles owned since new. Looking for a smaller muffler to replace this huge ass trash can under the Jeep. I absolutely do not want a loud replacement. I would like something as quite as stock but could live with a little more noise but not “hell yea!” loud.

Also, I’m not interested in replacing anything forward of the cat. I want all that intact. Just looking to lose a little weight and some bulk.

What are your suggestions? Thanks y’all.
 

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Gunnery Sergeant USMC (ret)
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I had a muffler shop cut just aft of the pipe right below the driver seat and weld in a dynomax muffler and then repipe from there to exhaust out the back. Freed up lots of room.
 

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i think any smaller muffler you out in will be louder than the old one. i think i used to use a California turbo muffler if i remember correctly it was bot bad and pep boys have them.
 

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it's a v-6 ; how loud is it gonna get or good can it ever really sound? :wink_animate:


seriously, the Dynomax mufflers are the best sounding , lower priced option on the 3.8 or 3.6 in my opinion. Initially sound a little loud but quickly mellow to a suitable growl that isn't rattly or piercing nor like a slammed Honda fartcannon.
I use the dynomax , pre-axle dump but others really like it ,together w/ a resonator , on the Pentastar like OPs.

Somebody on some other site has a good write-up or video of it being used on an orange Pentastar JK , iirc.





 

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On those Dynomax mufflers, what size can you fit in between the frame rails and driveshaft? I'm looking to change mine up too. I had a Flowmaster 40 in the back, that fucker was loud. Changed it to a Flowmaster 50 (little larger) and it's loud too. Hasn't mellowed at all.

Hard part for me is having a 2 door, so not much room in that area front to back.
 

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Random Dude
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On those Dynomax mufflers, what size can you fit in between the frame rails and driveshaft? I'm looking to change mine up too. I had a Flowmaster 40 in the back, that fucker was loud. Changed it to a Flowmaster 50 (little larger) and it's loud too. Hasn't mellowed at all.

Hard part for me is having a 2 door, so not much room in that area front to back.
The Flowmaster 50 series was the biggest can I could fit in front of the axle on my 2 door, and I wanted less sound.

EDIT: Note - evap needs relocation to put a Flowmaster 50 in front of rear axle on a 2-door.

I relocated the evap. to make room for the FM50, which was a huge upgrade over the MBRP muffler that was there.
I actually ran a Supertrapp diffuser for years to make the MBRP tolerable. Tailpipe was impossible at that time.


Recently I added a resonator behind the rear axle and it knocked off a solid (estimated) 3dB :D



Because of self-created obstacles, it took a bit of fiddling to get it done on my Jeep.
Hopefully it would be much easier if your rear suspension is not "odd" :laughing:.

Here's what I did: https://www.jkowners.com/forum/scrapbook-picture-request/88448-exwrenchs-oddball-mods-sneaky-stretch-8.html#post4460896
I'd do it again in a heartbeat - I'm super happy with that modification.
 

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Random Dude
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Dudes. I have a 2018 JKU Sahara. 40k miles owned since new. Looking for a smaller muffler to replace this huge ass trash can under the Jeep. I absolutely do not want a loud replacement. I would like something as quite as stock but could live with a little more noise but not “hell yea!” loud.

Also, I’m not interested in replacing anything forward of the cat. I want all that intact. Just looking to lose a little weight and some bulk.

What are your suggestions? Thanks y’all.
If you don't want to relocate your evap. canister, you could put a resonator inline ahead of the rear axle and a relatively large muffler post-axle. There's a straight enough section forward of the axle that cutting in a resonator is a cake walk. Rough rule of thumb: case volume is directly proportional to muffler effectiveness - there's no free lunch.


it's a v-6 ; how loud is it gonna get or good can it ever really sound? :wink_animate:
Loud enough to drone obnoxiously, and loud enough to sound like absolute dog shit (most V6s do, IMHO).

I hated my 3.8 through the MBRP once I cut off the tailpipe at the rear axle (necessary evil at the time).

The Flowmaster 50 pre-axle made it tolerable / OK, but adding a resonator after axle and a full tail pipe brought it back to "good".

If it's not fast, it shouldn't sound furious :laughing:
 

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On those Dynomax mufflers, what size can you fit in between the frame rails and driveshaft? I'm looking to change mine up too. I had a Flowmaster 40 in the back, that fucker was loud. Changed it to a Flowmaster 50 (little larger) and it's loud too. Hasn't mellowed at all.

Hard part for me is having a 2 door, so not much room in that area front to back.
the "Crawler" pre-axle dump is a 22" long can that iirc is about 11-13" diameter? It never has even touched the skid for the evap canister that is between it and the rear Woods shaft. Plenty of room on mine with the Dynomax 39516 can in that spot between frame and evap skid.




I have heard others say that about the MBRP can oin thre 3.8s , @ExWrench . The new setup kicks ass! Great idea. I can't use that area above axle but if I could I would try what you've done there. Nice!
 

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I had the Dynomax crawler set up. I really liked the set up but couldn't stand the drone at highway speeds. And this was with 37" Iroks and stereo appropriately cranked up. Went back to stock and I'm still looking.
 

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V8 dreams
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Another vote for the dynomax pre-axle dump...quietest and least obnoxious i could find. Also, it’s cheap as hell and you can DIY. I recently bought another one of these mufflers off amazon for my brother’s bday for $62. I wouldn’t say it sounds good, but it’s acceptable lol. Nothing i listened too impressed me, but we all know you just don’t make a V6 sound good, ain’t happening
 

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I have the mbrp cat back, it's inexpensive and doesn't take up much room but it's loud. I don't mind it but it doesn't fit your requirements
 

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I really wouldn't know which one would fit your requirements but don't even look at Gibson (definition of a fart pipe).

My brothers daughter and kids were in the Jeep a couple of weekends ago , a ricer JK pulled up next to us (Gibson Sticker and all) and took off from the light and the little girl said "That Jeep just farted,Hehehe".

I laughed so hard tears were causing vision problems , had to pull over and clean the sunglasses.:laugh:
..
Ryan that one is for you .
 

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The Flowmaster 50 series was the biggest can I could fit in front of the axle on my 2 door, and I wanted less sound.

EDIT: Note - evap needs relocation to put a Flowmaster 50 in front of rear axle on a 2-door.
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How did you get that one with the inlet and outlet on the same side? Wasn't that model discontinued?
 

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Random Dude
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How did you get that one with the inlet and outlet on the same side? Wasn't that model discontinued?
I ordered this: https://www.summitracing.com/parts/flo-842554

. . . and just now learned it's unavailable, so likely it is discontinued :(

Probably due to insufficient demand vs. other configurations.
If they sold 5000 a year, it's worth keeping the part number active . . . 500, not so much.
 
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