I am trying to decide whether or not to leave or gut the cat. Is the cat the restrictive part or is it the muffler. Im not really looking for louder noise just something to lower my egt's. Thanks guys.

 

The cat an the muffler are 2 different things on the new cummins i believe. Im not to sure tho i dono alot bout the new CTD. But if im right an if u take off the cat an muffler it would be very loud, but i liek the way they sound cat an muffler off, sounds like a big rig to me an i like that. So if u aint lookin for alot of noise then just take the muffler off an be done wit it. I hope im givin u the right info, chime in u other guys an tell me if im right

 

Removing both would lower your EGT's, The price is a loud raspy rig. I loved it on mine. The cat I would say is probly the worse part. With both removed you will have a drone on a load. You can try it then always put a muffler on it if you dont like it. I didn't really hear mine unless the windows were down but man every one else sure did. The looks were great, and no one asked if it had a hemi any more

 

CATs on diesels aren't like on gassers where you can't remove it?

 

I've heard of several guys gutting theirs on the Kali SO's and the 04.5's and guess what, it didn't do squat for them. I am sure there is some restriction, there has to be, but a while back there was a thread here and on TDR that said it didn't help.

On the other hand, someday they're gonna regulate these things just like the gassers and it's about $400 bucks to replace that hollow kitty.

I left mine alone... my $0.02

 

The muffler is the more restrictive area of the exhaust. On the 600s we have had many customers remove the muffler and install an Aeroturbine directly on the outlet to the cat and use straight pipe to connect to the tail pipe. This actually works very well and does not make the truck too loud.