Gutting Cat?

[Tmac0220]

I have a LLY, has anyone ever gutted the cat, then put it back on?

[Maine Towing]

Had a friend do that on his Cummins, used a long pry bar, has worked for quite a while now.

[784x4chev]

I did it to mine before I got a 4" system. If you just use a pry bar or a rod you won't get all of the material out. I cut mine apart and gutted it then re-welded it.

[norcalrider]

Sorry to thread jack, but the guys who gutted theirs, did you pull any codes? did you finger stick? thanks

[1953drtelco]

I gutted the Kitty last year. Your not going to get all the material out but the small amount left will not stop any flow. I used a few steel concrete stakes and short pieces of rebar and a nice 5 lb hammer. It was a 3 beer job with noticeable results. I didn't throw any codes on my LLY, but I'm one of the lucky ones with a FE9 truck in Calif.

It does allow a bit more coal being displayed during the snap test, but not enough to fail the test.

[skleppy]

IF you're not going to upgrade teh exhaust behind it, you probably won't notice that much of a differance. You'd be surprised at how restrictive the muffler is when you see it in comparison to an aftermarket.

[1953drtelco]

I ended up running a 4" exhaust with a Corsa Muffler behind the gutted Kitty. Corsa muffer has a flow through design with no drone at highway speeds....Nice and quiet even when towing

[D_R_C]

Originally Posted by Tmac0220

I have a LLY, has anyone ever gutted the cat, then put it back on?

Do you have to have the cat for emissions?
If not you can get a front pipe for around $120, my Diamond Eye Quiet Tone cost about $135 shipped.
And what is the rest of the exhaust you have on, still stock?

Originally Posted by skleppy

IF you're not going to upgrade teh exhaust behind it, you probably won't notice that much of a differance. You'd be surprised at how restrictive the muffler is when you see it in comparison to an aftermarket.

I've been saying this for years but always get blasted from a few.


For the OP,
I have a LMM and first deleted only the muffler, a very noticable difference.
After 3 months I deleted the DPF and left the cat on which helped even more and sounded pretty good.
I ran that way for 3 years, then ditched the cat and went with Diamond Eye Down pipe and Quiet tone front pipe and blocked the egr, there was no real noticable gains considering the cost, except for the a little deeper exhaust sound.

I would first delete the stock muffler, maybe gut the cat or install a aftermarket front pipe. Depending on your emissions laws if they do visual inspections.
You might have to put a aftermarket muffler on to tone it down, if you gut the cat or do a front pipe.
If you leave the cat alone, the exhaust sound should be good without a flow thru muffler.

[dirtymax82]

Originally Posted by D_R_C

Do you have to have the cat for emissions?
If not you can get a front pipe for around $120, my Diamond Eye Quiet Tone cost about $135 shipped.
And what is the rest of the exhaust you have on, still stock?



I've been saying this for years but always get blasted from a few.


For the OP,
I have a LMM and first deleted only the muffler, a very noticable difference.
After 3 months I deleted the DPF and left the cat on which helped even more and sounded pretty good.
I ran that way for 3 years, then ditched the cat and went with Diamond Eye Down pipe and Quiet tone front pipe and blocked the egr, there was no real noticable gains considering the cost, except for the a little deeper exhaust sound.

I would first delete the stock muffler, maybe gut the cat or install a aftermarket front pipe. Depending on your emissions laws if they do visual inspections.
You might have to put a aftermarket muffler on to tone it down, if you gut the cat or do a front pipe.
If you leave the cat alone, the exhaust sound should be good without a flow thru muffler.

I have the DPF deleted and have been trying to decide if I want to delete the muffler and cat. I want better flow but don't want to yell inside my truck when I'm pulling my boat. Should I just go with a performance muffler?

[Maine Towing]

I can tell you that my set up is still very quiet in the cab, not any difference from what I can tell, and my truck lives at 26,000 lbs, I was worried about the same thing. Now if I have the back window down and pass a fence, wall, or other object the exhaust reflects off of I can definitely hear a difference, but with the window up there is no difference.