What is everyone’s thoughts on removing the muffler from a 4.0 TJ?

[S.McArthur]

You screw up the back pressure as well, ever wonder why these dumb ass straight piped trucks make an ass load of noise and don't go anywhere?
These engines are designed for efficiency, not like the old school non regulated vehicle engines from days past.
You will make more noise; not power

 

[Vasq]

I think @Vasq just installed a turbo muffler that he claims is actually too loud for him. Maybe he'll share what brand and model it is, so you too can enjoy the rumble...

*poof*

Mufflers?!
Actually I had a dynomax super turbo muffler and I loved it, not very loud at all and above 2k rpm it was exactly like stock. Below 2k it just had that nice rumble sound I liked, wasn't loud but just meaner. and at idle the same thing, not loud, but just sounded mean. Alas... that muffler was way too long for my tummy tuck
Currently I have a "Thrush welded" muffler. At the time I was in a pinch, and needed a muffler since I didn't anticipate my old one not working out. I bought it based on its overall dimensions, and it was super cheap (like 30 bucks). Fits great with the TT, super annoying loud. Really cool rumble at idle, soon as you hit the gas it drone's until 2k, doesn't do much until over 3k and then its just roaring.
My fix, although I haven't implemented it yet, is the "thrush hush" which I've heard good things about.

Can't imagine having no muffler would sound good.

You need to be below the age of 25 to understand this one I think

In all honesty, when I was that age and younger I liked loud. These days, the last thing I would want to drive is a loud vehicle. I guess I'm becoming boring as I get older, haha.

I completely agree. I use to feel so cool with a loud exhaust in my early 20's on my YJ. Now that I accidentally have a loud exhaust at 30, I try to slink around without being obnoxious.

 

[Cole]

I've got a muffler with holes in it and it sounds loud and annoying. Was planning on scrapping it and finding an old new one without holes... I'll trade you straight up. Do whatever you want to it!

 

[ranger101]

I have a Dynomax Super Turbo as well dumped before the axle. Drones a little bit, but it’s much quieter than the Flowmaster 40 I had before.

 

[Jerry Bransford]

I just replaced my totally blown out muffler 2 weeks ago. It's so much nicer to drive now. But then I'm old.

 

[RiverDawg24]

Back when I was building my own suspensions...long arm triangulated 4 links in the rear... Figuring out how to package a huge muffler so it would be quiet was one of the biggest issues.

I can't stand to be around obnoxiously loud rigs while wheeling.

Don't be "that guy" on the trail

 

[L J]

I heard it sounds pretty nice

you heard wrong

 

[Vasq]

I have a Dynomax Super Turbo as well dumped before the axle. Drones a little bit, but it’s much quieter than the Flowmaster 40 I had before.

not sure if you dumped it before the axle due to a restriction or not, but it should sound really nice if you run it all the way out to the rear frame

 

[Mumblewood]

It sounds illegal here in Washington, especially if the Forrest service catches ya. You must have a spark arresting muffler in the woods here or big fines and possible impounding

 

[ranger101]

not sure if you dumped it before the axle due to a restriction or not, but it should sound really nice if you run it all the way out to the rear frame

I was installing a new rear track bar a few days before a beach trip. Found out my exhaust was in the way so I had to whip up something quick. It’s a temporarily permanent setup lol

 

[Equilibrium31]

It sounds stupid and obnoxious, trust me.

100% this. I've never heard a TJ without a muffler, but I don't need to either. I find loud sports cars obnoxious as it is, but even if a TJ would give some sort of decent sounding rumble without a muffler, it's just a ridiculous idea because TJs aren't muscle cars. The beauty in them is their capability that's more from suspension than anything particularly notable being under the hood.

 

[Vasq]

I was installing a new rear track bar a few days before a beach trip. Found out my exhaust was in the way so I had to whip up something quick. It’s a temporarily permanent setup lol
View attachment 128676

yeah I know how that goes. Off topic real quick, is that an old Doosan or mori seiki in the background?
Looks 1990's..

 

[1997JeepTJ]

I've got a Magnaflow catalytic converter assembly and a Dynonax Super Turbo cat back system. Sounds nice, looks good, fits well and even clears the trailer hitch. I've had plenty of loud exhaust systems on Mustangs. The Jeep has a mild throaty sound.

 

[06lj]

Now that I accidentally have a loud exhaust at 30, I try to slink around without being obnoxious.

Ouch!
When I was reminiscing on being younger I was thinking of my early 30's.

 

[ranger101]

yeah I know how that goes. Off topic real quick, is that an old Doosan or mori seiki in the background?
Looks 1990's..

It’s an old Cincinnati Lancer we have 3 of them that our shop bought brand new back in the day. I’d say right around the time I was born(1994) we have 5 Mori Seiki mills from this decade haha and 4 Mori Seiki lathes with live tooling and 5th axis abilities.

 

[Vasq]

Ouch!
When I was reminiscing on being younger I was thinking of my early 30's.

HAHA my bad. I'm an old soul, what can I say

It’s an old Cincinnati Lancer we have 3 of them that our shop bought brand new back in the day. I’d say right around the time I was born(1994) we have 5 Mori Seiki mills from this decade haha and 4 Mori Seiki lathes with live tooling and 5th axis abilities.

ah gotcha! I could tell by the paint color it was 90's but couldn't make out enough of the control to know what it was. I do in house maintenance for a CNC shop here in WA. We just got our first live tool lathe, but man to we have a huge "era" spread for machinery..

anyways.. I'll stop derailing this thread with my nerding

 

[ranger101]

HAHA my bad. I'm an old soul, what can I say


ah gotcha! I could tell by the paint color it was 90's but couldn't make out enough of the control to know what it was. I do in house maintenance for a CNC shop here in WA. We just got our first live tool lathe, but man to we have a huge "era" spread for machinery.

Haha I can relate to that! We have a lot of nice CNC’s but we have a decent amount of manual machines too. We also have a couple machines that were made for WWII, a G&L horizontal boring mill and a Bullard vertical lathe.

 

[GASnBRASS]

Back to exhausts, you will not get a throaty sound like you would with a V8, the pulse spacing and count is wrong.
Many of the louder mufflers for the 4.0 sound ok at idle, but ricer at throttle. Yuk.

As far as needing backpressure that's a common misconception. In an N/A engine you don't want backpressure, you want scavenging. Each exhaust pulse creates a high and low pressure around it (think sound waves). Tuned properly that low pressure can help pull the next pulse out of the cylinder. But too small of a pipe becomes restrictive; too large and the exhaust velocity drops and scavenging suffers.

 

[Fouledplugs]

100% this. I've never heard a TJ without a muffler, but I don't need to either. I find loud sports cars obnoxious as it is, but even if a TJ would give some sort of decent sounding rumble without a muffler, it's just a ridiculous idea because TJs aren't muscle cars. The beauty in them is their capability that's more from suspension than anything particularly notable being under the hood.

Tell that to the guys who went with 2.5 instead of the 4.0

 

[PatMc]

These engines are designed for efficiency

Do you know something we don't?