Stock Muffler

[Keithbickford]

I’ve been wondering about the exhaust paths through the stock muffler and could not find any info. I was curious how muffled the bypass path is. So, today I took my muffler off and looked inside.
The primary paths through the muffler are the bypass paths. They are perfect mandrel bent 3” pipe from inlet to outlet. The angles are also non restrictive despite the inlet pipes coming in at 90°. Immediately after the inlet pipes there are nice mandrel bent radius pipes to direct the flow to either side. Then it’s straight out into the bypass valve. In the straight length of pipe, there’s a 2” hole that allows exhaust to enter the muffler cavity when the valves are closed.
So, if you’re considering ditching the muffler to make more power, dream on. There’s no restriction at all. I attached two photos. I shined a flashlight into the inlet and took a photo of the outlet. Then I shined the light into the outlet and took a photo of the inlet. As you can see, there’s nothing in the way. I also dropped a large nut through the muffler. It came right out.

There’s still the fact that the muffler hangs down and the tips hang down even lower. The tips can’t simply be rotated because there are alignment pins. I ground off the alignment pins and rotated the tips more horizontal.

 

[onfire392]

Excellent !

 

[EBYCREEK]

I think most people that 4WD in the rocks will need to add a skid plate to the muffler. I wouldn't even have a muffler today had I not installed a skid plate.

 

[bluej]

This is my solution for most of the summer when I’m out rock crawling. I have a metal cloak skid plate over the muffler and just removed the tips. It only takes about 30 minutes to reinstall.

 

[Jeepsterman]

I changed mine out, not for more power, but for aesthetics and clearance. With closed baffles it was actually quieter than stock and open it was noticeably louder. Well worth the $ IMO.

 

[Keithbickford]

I changed mine out, not for more power, but for aesthetics and clearance. With closed baffles it was actually quieter than stock and open it was noticeably louder. Well worth the $ IMO.

Looks good. A few companies put a lot of research into their exhaust systems. Borla is one of them.

 

[Infidel09]

I decided to take mine off....you can use the exhaust tips and attach them as seen in the picture. I plan on having a muffler shop run a set of quad tips out the rear - I was quoted $150 and they will make it look just like the magnaflow cat back system for $2500....

 

[Keithbickford]

I decided to take mine off....you can use the exhaust tips and attach them as seen in the picture. I plan on having a muffler shop run a set of quad tips out the rear - I was quoted $150 and they will make it look just like the magnaflow cat back system for $2500....

$150 would be a screaming deal if they can do it well. My shop quoted me twice that for house bent aluminized steel pipe.

 

[TinaBeans]

I’ve been wondering about the exhaust paths through the stock muffler and could not find any info. I was curious how muffled the bypass path is. So, today I took my muffler off and looked inside.
The primary paths through the muffler are the bypass paths. They are perfect mandrel bent 3” pipe from inlet to outlet. The angles are also non restrictive despite the inlet pipes coming in at 90°. Immediately after the inlet pipes there are nice mandrel bent radius pipes to direct the flow to either side. Then it’s straight out into the bypass valve. In the straight length of pipe, there’s a 2” hole that allows exhaust to enter the muffler cavity when the valves are closed.
So, if you’re considering ditching the muffler to make more power, dream on. There’s no restriction at all. I attached two photos. I shined a flashlight into the inlet and took a photo of the outlet. Then I shined the light into the outlet and took a photo of the inlet. As you can see, there’s nothing in the way. I also dropped a large nut through the muffler. It came right out.

There’s still the fact that the muffler hangs down and the tips hang down even lower. The tips can’t simply be rotated because there are alignment pins. I ground off the alignment pins and rotated the tips more horizontal. View attachment 52131View attachment 52132

So…. How did it sound without the muffler? C’mon, we know you HAD to at least start it up w/o it just to hear the glory.

 

[Keithbickford]

So…. How did it sound without the muffler? C’mon, we know you HAD to at least start it up w/o it just to hear the glory.

I drove it about 30 miles. It vibrated the cabin and didn’t sound any better, IMO.
Since the bypass goes straight through, the only difference was that it exited under the body, which is not ideal for any vehicle.

 

[TinaBeans]

I drove it about 30 miles. It vibrated the cabin and didn’t sound any better, IMO.
Since the bypass goes straight through, the only difference was that it exited under the body, which is not ideal for any vehicle.

Had to pull the muffler on our 4xe to get a Metalcloak 3-1/2” lift under it. The rear sway bar was too close and would hit it with every bump. Put a MBRP pipe where the muffler was so the exhaust would exit behind the rear bumper. It really isn’t that much louder and there’s now tons of departure angle gain over the stock muffler.

 

[Earl 392]

Had to pull the muffler on our 4xe to get a Metalcloak 3-1/2” lift under it. The rear sway bar was too close and would hit it with every bump. Put a MBRP pipe where the muffler was so the exhaust would exit behind the rear bumper. It really isn’t that much louder and there’s now tons of departure angle gain over the stock muffler.

 

[TinaBeans]

Yeah, the muffler is lower on the 4xe due to the battery pack and heat shield. Makes working on the e-brake a bear too. I wonder if anyone has tried an MBRP pipe on the 392?

 

[OffRoadMedic392]

This is my solution for most of the summer when I’m out rock crawling. I have a metal cloak skid plate over the muffler and just removed the tips. It only takes about 30 minutes to reinstall.

I plan to do the same, I took mine off with ease when I painted them black and thought this would be an easy solution to protect the tips.

Have you noticed any difference in sound "profile" as the exhausts are facing to the outside with the tips off as opposed to facing rear with the tips on.

 

[Keithbickford]

I plan to do the same, I took mine off with ease when I painted them black and thought this would be an easy solution to protect the tips.

Have you noticed any difference in sound "profile" as the exhausts are facing to the outside with the tips off as opposed to facing rear with the tips on.

I’m interested in how you painted the tips black and how they look. With mine turned up level, they’re barely noticeable actually.

 

[392mike]

I decided to take mine off....you can use the exhaust tips and attach them as seen in the picture. I plan on having a muffler shop run a set of quad tips out the rear - I was quoted $150 and they will make it look just like the magnaflow cat back system for $2500....

How was the sound compared to stock? This looks like the ideal solution if no change in sound.

 

[OffRoadMedic392]

I’m interested in how you painted the tips black and how they look. With mine turned up level, they’re barely noticeable actually.

I used Rustoleum high heat paint, it came out flat black like you'd imagine on a grille.
I was happy with it until my neighbor showed me his newly painted Firebird exhaust tips in gloss black.
He used gloss caliper paint, safe to say I'll be doing the same soon.

 

[Earl 392]

I used Rustoleum high heat paint, it came out flat black like you'd imagine on a grille.
I was happy with it until my neighbor showed me his newly painted Firebird exhaust tips in gloss black.
He used gloss caliper paint, safe to say I'll be doing the same soon.

Do you have a picture of caliper paint?

 

[HYDROBLU392]

I haven’t touched the stock muffler but did install the MRT h-pipe deleting the resonator. Sounds awesome. Louder than stock but no drone and not annoying at all.

 

[Keithbickford]

I haven’t touched the stock muffler but did install the MRT h-pipe deleting the resonator. Sounds awesome. Louder than stock but no drone and not annoying at all.

An H pipe is the ideal solution for a V8 muscle car, which is what we have. It is less raspy than a Y pipe and is ideal for lower rpm power, whereas an X Pipe is ideal for higher RPM power. The H pipe is also better at reducing drone. Y pipe has a bit more exotic sound. So they both have their place and Jeep would have been wise to install an H pipe from the factory.