lgp9999

My '98 12v does not sound factory (despite the factory exhaust), so I climbed underneath it to take a peak to see if it had an aftermarket muffler. It is all 3" straight pipe except for a large, cone like muffler/resonator thing. It makes a "pling" when I tap on it, so it doesn't appear to be a packed muffler of any kind. There are no brand markings on it that I can see.

Does anybody have a pic of the factory muffler to help me figure out what I've got? Thanks.

oldwhite12v

sounds like you've the factory cat with no muffler. stock system has a cone shaped cat as well as a large cylindrical muffler

waldersha

At least on mine the cat went to 4" on the outside. For some reason 3" from the downpipe to the cat, 4" into the muffler, then 3" back out of the muffler to the tailpipe. I don't know about the 98, but what you are describing sounds like the cat. By the way, the stock muffler on these things is massive. Mine was about 3.5 feet long.

Tommy93w350

Jerk all of it out and install a 4" turbo back from WarpSpeed. I've been very happy!!!

lgp9999

Hmm, I was under the impression that 12v CTDs didn't get a cat. I'm seeing nothing that really resembles a muffler down there... I'll take a pic if I can find any dry weather in the near future... nothing beats laying on your back in a puddle if you know what I mean.

Tommy, yes I'll be getting a 4" turbo back system. I haven't decided on a brand yet, but I will take a look into the WarpSpeed. Thanks for the reccomendation.

Racer9

Heres what came off my '96, muffler to the left, cat is the rustier thing on the right.

lgp9999

Racer9, that answers my question. As a few said above, all I have is the cat, and no muffler. It sounds pretty bad ***, and not too loud either.

Rammer

Yes the 12 valves had cats, when the 98.5 with the 24 valve can out they didnt have cats. My 97 had one and my 2001 dont.

lgp9999

Well I pulled my stock exhaust on Saturday night to install my 4" mandrel bent system ordered from summit (as mentioned here: https://www.dieseltruckresource.com/....php?t=132300), and not only was the stock muffler cut out and replaced with straight pipe, but the factory cat was gutted. It was just a big chamber. My 4" system is quieter, but even the factory exhaust modified to straight pipe wasn't all that loud... still more engine noise than exhaust noise.

Rammer

Can you tell a difference with the 4 inch on it?

lgp9999

Yeah, it definitely spools quicker. Other than that, nada.

AllPlay

2nd the Warpspeed exhaust. Sounds great. Great price. Easy to install.

OUTDOORSMAN

Here is my stock muffler. On the day we left for alaska. We made it about 12 miles from my house and I heard this noise. I am still running without it. I wouldnt mind finding a used one that someone upgraded.

dieselfuelonly

Looks like the easy way to straight pipe it

Do you have something set up to keep that exhaust from coming through you're cab?

OUTDOORSMAN

We dont get any exhaust in the cab but the back of the truck in the cap does. Good thing I noticed it before I hauled the dogs in the back. I do need to fix it. When we use the back for clothes or gear it does get a funk to it. I just dont have the cash for a new system right now. ALSO it really keeps the bed of the truck HOT... Seriously warm compared to outside temps. Temp taken with digital thermometer, 89 degrees bed temp, 60's outside air temp. Running on the highway at 70mph.

Shoot I still havent replaced the rear tire that I blew out. I wonder if I could find 3 more spare tires on steel rims to run on the truck. Anyone have any idea where to look? I still need to reach a member from here to help me get the new tire.