Exhaust Noise

[JeepSola]

I have a 97 tj with the 4.0. It had a bassy rumble in the exhaust. I had a Walker quite flow installed but it's just a loud if not louder. I discovered that it has no cat installed. Is this why it's so bassy and loud?

 

[macleanflood]

Might have a cracked exhaust header.

Mine looked fine until I pulled it and it split into three pieces.

Donut seal at the bottom on the header also loves to leak.

-Mac

 

[JeepSola]

If it was the header, wouldn't the sounds come from up by the engine? Also, how do I check the header?

 

[macleanflood]

Yes, true.

Visual inspection or disassembly...not hard at all to pull on a 97.

-Mac

 

[KennethS]

My cracked manifold made a rhythmic tapping sound (exhaust leak).

The catalytic converter does reduce or “muffle” the exhaust noise.

Does the exhaust pipe go all the way to the rear bumper? Full length exhaust pipes also reduce tje sound level.

 

[JeepSola]

My cracked manifold made a rhythmic tapping sound (exhaust leak).

The catalytic converter does reduce or “muffle” the exhaust noise.

Does the exhaust pipe go all the way to the rear bumper? Full length exhaust pipes also reduce tje sound level.

Yeah, the exhaust pipe is pretty much standard length. I do have a ticking noise that I think might be a lifter.

 

[macleanflood]

Could download a db meter app on your phone and hold it a couple of determined positions...3' immediately behind the exhaust, under the skid plate, and maybe sitting in the driver seat about ear level...capture db levels at idle, 2k, 3k.

I could get you my numbers... maybe some other folks can too and we can see if yours in "louder."

-Mac

 

[TJ Jim]

I have a 97 tj with the 4.0. It had a bassy rumble in the exhaust. I had a Walker quite flow installed but it's just a loud if not louder. I discovered that it has no cat installed. Is this why it's so bassy and loud?

YouTube a video/sound bite so we can tell you more

 

[JeepSola]

I did the seafoam thing and noticed leaking around the down pipe connection. Didn't see anything around the manifold. I know that it has a really bad bassy rumble.

 

[bluescapegoat]

Sounds like you just have drone, brought on by the lack of cat(s)?

If it's a particular frequency and spot in the rev range you can use a calculator to find the proper length for, and build, a helmholtz resonator. I've been toying with the idea of doing just that, but the problem is really space. I had one on my first gen Raptor and it was pretty remarkable the reduction in drone.

It doesn't really work for the entire rev range though, just if you're trying to target a certain annoying pitch at, say, cruise speed