I know the cheap thing would be to straight pipe the stock exhaust. But I have a couple issues with noise. First is that I use my truck as a service vehicle in an upscale neighborhood and the other is hunting. Mike said in some post that you could hear his truck coming for a mile. Not good for hunting. Like typical, I want my desired outcome for the least amount of money. I wish to have better flow of air through the engine and have it quiet. Is there a way to go from my stock muffler to straight pipe by pulling a lever? I'd be willing to do it from outside the vehicle.

My 3500 has Diamond Eye 4" TBE with a muffler, and it's not very quiet.My 2500 24V had Diamond Eye 5" with muffler and 6" tip, and I think it was more quiet than this 4" setup. Granted, the 12V has a different exhaust note than the 24V, but noise levels between the two are completely different.

I'm getting conflicting info. Didn't think that happened here. Lol.

My system is stock 2001.5 2500.

I have 2 units on my exhaust system. Front one is rectanglish about 14" square. Rear one is about 30" long and round. Some say the front one is a catalytic converter, others say muffler. Some say the rear one is muffler and others say resonator.

If the front is a catalytic I should be able to cut it off without much increase in noise and improve exhaust flow. Do we need a poll to vote on which is correct? Lol.

Buy a mbrp turbo back 4" exhaust with muffler. They are cheap and give a nice sound without being too loud. Ive heard it called a cat and a resonator. I would have to look in the fsm to see what it is offically called

I thought all second gens where pre-emissions. IE no catalytic converters. So there should be a resonator then a muffler, both simply for sound

Federal trucks don't have cat/resonators, CA trucks had them if I remember right

I thought all second gens where pre-emissions. IE no catalytic converters. So there should be a resonator then a muffler, both simply for sound

The '96 model year had a cat on it. Mine plugged and gave me fits until I figured it out. Joe, the cats were round but had a serial tag on them. Yours is a resonator.

The 01 FSM shows first a resonator and then the muffler with no mention of a CAT. Mine was definitely NOT a CAT. I have to agree with Tom. 

Good luck with a "quiet" free flowing exhaust...it's a cummins. I love my 4" mbrp exhaust. It sounds great and isn't too loud unless you romp on it. Straight piped will set every alarm off in the parking garage but flows noticeably better. I would get the 5" if I could do it again though, isn't as loud but is deeper sounding than a 4"...there's a 3rd gen that drives by house everyday with a 5" exhaust and it sounds/feels awesome!. My buddies 06 commonrail runs a diamond eye 4" with a 2 mufflers to tone it down for customers.

On my 2010 Hemi earlier this year a guy backed into me and damaged my rear exhaust pipe and kinked it to the point I had to take it off behind the muffler, I have the single exhaust on mine and the resonator is the last thing in line in fact there is only about 18" of tail pipe past it, It has dual cats and pipes going into the factory muffler then out as a single so I ran without the resonator and tail pipe for about 2 months trying to decide whay I was going to do and that thing was obnoxious loud in the cab without the resonator I decided to go back with the stock tail pipe and resonator, life is much more peacefull now, I couldn't believe how much it quiets the exhaust down and especially as far back as it is.

 

On extended cab diesels I am a firm believer in the 36" FTE resonator hands down run it alone as far forward as possible and if quieter tail pipe is wanted then it is easy as pie to put a muffler behind it, worked wonders on my 02 and I have been in several other cummins rigs before and after the FTE resonators and it is amazing how much quieter it is in the cab with no drone and the long ones help quiet the exhaust a bit too and are zero restrictive.

Edited January 9, 201411 yr by Wild and Free

I have the 4" mbrp w/ muff and it is extremely loud in the cab until it seems to warm up. The other day I was crusing empty and not towing on freeway and couldn't hardly stand the noise. I floored it and boosted to about 35 psi for a few seconds and all cab noise was gone. Anybody have similar situation going on or know why this might happen. I know the noise level when towing my 5ver while exhaust is cold will be unbearable.

Edited March 8, 201411 yr by rseabur

4" with muffler should not be loud. I know dozens of cummins trucks running that same exhaust (I have personally owned two with it) and it is quiet in the cab. I would be looking at where your downpipe clamps to the turbo and all your other clamps

That's what I heard and why I bought it. Just thought it was very weird as to why it got quiet after it boosted the turbo hard. Took the exhaust to the tone that I think it should have. I will check all my clamps and make sure they have not loosened up

On mine the rod that was welded to the exhaust for a hanger failed. It was the hanger at the tranny(mines a manual and not an auto). The weld started failing and it came loose from the pipe slowly actuatlly pulling a piece of the pipe with it. I ended up with a 1/2" by 6" slot in the pipe. Over time it got louder and louder until I found it. Did not help that is was directly under the passenger side floor board. If it is getting that loud it shouldn't be that hard to find.

One thing about you Cummins guys.... even with stock exhaust I know none of you could ever be a burglar

I had the same thing as Dripley happen on mine. That mount at the tranny pulled loose from the pipe and ripped a hole. I just have a 4in straight pipe all the way back from the turbo. It does drone a bit when towing heavy and I am around 2k rpms, but otherwise the turbo is MUCH louder in the cab than the exhaust it.

As for it being louder when cold, I would also check clamps and what not. Seems like something is seperating while its cold but closing up whenever it warms up a bit. Hope its not a cracked manifold or something. I think you would really know it if it was though.

Even on my stock exhaust when the tail pipe rotted and had a hole it was a lot louder in the cab.

It only about a month old so don't think mount it riper out or it is rotted out. Might just he nature of beast. Cant check it out until I get. It back. Lower ball joint had to be machined out. I knew I was a gm guy for a reason.upper came out fine but lower rivets had to be machined out or buy a.whole.new lower control arm. Will check out monifold for cracks and check all connections when I can get it back from the shop

 

I recently installed a 5" straight through ShuttleWorth muffler on my truck. It gives a nice deep tone but is not obnoxious. It also cut the resonations I was experiencing in the cab back to almost nothing.

They are more of an industrial application and I am impressed with the build quality. It was on an old GM dump truck my cousin scrapped out. The exhaust looked brand new so I snuck under neath with a cordless sawzall and helped myself.

Tone stays the same at the tip. So it just a fluke thatfor the first 10 to 15 miles it is extremely loud in the cab until I boost the crap.out of the turbo. After that it is like driving a gasser in the cab but tone at tip still has that nice tone.