I've had my truck for 7 years, at least 6 of it with louder exhaust. The older I get the more I got tired of the sound. After 5 mufflers I decided to try the stock muffler and to my surprise all the claims that the muffler was restrictive have been proved to be false. I have plenty of power and EGT is fine. It is still louder than I remember with the stock exhaust. I'm debating on putting the CAT on also if it makes it quieter. What are your experiences?

 

I've got a buddy with a factory 07 with a cat and delete pipe. It's still pretty loud, but not nearly as bad as a straight pipe. He loves it, and I think it sounds great!
No kitty on mine, never had one.

 

If you don't tow, drone will not really be an issue and you can get away with anything.
BUT, if you tow or don't like highway drone, an exhaust with minimal muffling will drive you nuts.
I think the common rail Cummins sounds terrible straight piped but that's just me.

IMO, the stock muffler is very restrictive but the Cat converter is not.
The Cat will really cut down the drone without restricting flow.

Before my twins, I went thru several exhaust configurations.
1st up was to replace the stock muffler with a small, free flowing MBRP muffler. Just a little louder than stock, no drone when towing.
Then I removed the Cat. Quite a bit louder than stock, massive drone when towing, sounded terrible.

Re-installed Cat, a 2nd small free flowing muffler. Nice and quiet, no drone at all, free flowing and just a bit of attitude sound-wise.

Then I installed my twins and it actually got a bit louder than with the stock single turbo. Still no drone when towing, sounds nice and deep at idle.

So my current exhaust is twin turbo's, exhaust brake, stock CAT, 2 small free flowing mufflers, all 4 inch pipe, stock tailpipe.
I suspect my 2 small free flowing mufflers are nearly similar in sound to a large single free flowing muffler like the Donaldson that is popular.


Hope this info helps..

 

I removed the muffler and kept the catalytic converter. The cat reduces sound quite a bit. Truck is still quieter than a 12v with a muffler. There is a drone while towing uphill in top gear but I can still talk on the phone or with a passenger no problem. I don't like my vehicles too loud and I don't feel a need for a muffler.

 

I have the cat and a magnaflow muffler, drone can drive me nuts only if the back windows are open. Other than that I cannot hear anything and I like it that way.

 

I have a cat, 51 donaldson and mandrel bent tail pipe, she is deeper than stock, sounds nice and no drone when Im towing.

 

I removed the cat and kept the muffler. The truck sounds awesome and no drone pulling my boat. When I took the cat off, it weighed a ton. I tipped it over and a bucket full of soot came out. I imagine that, eventually, the cats get clogged. The muffler on our trucks is not restrictive at all; and from what I can tell, pretty high quality.