JeRM82

This may be better in the 8 lug forum, but it is about a gas truck so I figured that I would ask here. SO....I'm talking with a guy that I work with who had exhaust put on his 2002 2500 6.0 gas truck a ways back, and he tells me that one of teh cats is IN the muffler on one side. I have an 07 classic 1500 (same as an 06) that had a cat on each side and then a muffler. WHen I took it OFF to put my KOOKs on.....I didn't exactly look INSIDE Of it to see if there was a cat in it or not. Is what this guy saying TRUE abot one of the catalytic converters being INSIDE of the muffler itself? I could see there being a RESONATOR in there......but it seems like a cat would be in FRONT of the muffler almost up against the exhaust manifold and then the gigantic factory muffler itself......

Anyone know for SURE if there are three cats on the truck in question? The guy was just going off of what the stealership told him.......and is not a car guy.....it just seems ODD to me that a truck THAT big has an emmissions set up like that.....

TXsilverado

iTrader: (19)

not true. I have an 02 hd 6.0. the muffler was weird though. it was dual in, single out but the entry point on one side was dead ended into a wall. most likely for noise reduction but I always wondered why gm would run a dual style exhaust and dump one side directly into a shield. I run a HUGE dual in, dual out magnaflow with a built in x pipe and it sounds nice. just enough grumble to satisfy the gearhead in me, but not so loud as to upset the old grumpy man in me lol

2xLS1

iTrader: (25)

OEMs put cats close to the engine where exhaust gasses are hotter so they can get up to temperature quick and start working. A cat that far down stream in the exhaust wouldn't be very effective.

RezinTexas

this is GM's Helmholtz resonator

The early 6.0 2500 trucks had their factory cats 3-4 feet downstream of the engine.

2xLS1

iTrader: (25)

Early 6.0 2500 trucks must have different emission requirements. That is possibly why their P0420 and P0430 DTCs are set to No Error Reporting in their stock calibrations. It is not until 04 MY that those codes are monitored on those trucks.