2nd Gen Non-Engine/Transmission Service Life of Catalytic Converter?

[Mike Ellis]

I am approaching 150K on my '97 12 valve, which came from the factory with a catalytic converter. I have never taken it off because I wanted to keep it emissions legal and do my little part for clean air.



The other day I was looking at the truck, and started wondering how much good the cat is actually doing after nearly 8 years. Are cats expected to stay on vehicles for their entire life? If not, where do you get a replacement?



Many years ago, I had to check into a cat replacement for my Corvette (back around 1979) and the GM folks were wanting a gargantuan sum for a replacement - I seem to recall them quoting me nearly $1000. I ain't about to spend that on my truck's cat when it goes TU. I know a lot of people just remove them entirely.....

 

[Dual EE]

I only had 112k on mine when I pulled mine off 2 months ago. So mine was 10 years old. The cat was still solid and in good shape inside. I saved mine just in case.

 

[EBottema]

Hey-



As long as the catalyst is not broken on the insides and rattling around you are probably okay. The cat is prob a little plugged from all the soot though. I would say a diesel cat should be replaced every 250k miles. You mentioned the clean air, the engine runs worse with a cat b/c of the extra backpressure. You are running richer (more fuel) and running hotter. In my opinion, yank the thing. Emissions and getting the engine running at full efficiancy dont mix but they are both a trade off.

 

[AMink]

I had mine off when I put on the Rip's. That was at about 105K. I asked a muffler shop guy if I could see light through it, if it was OK. He said yes. You won't see much, but if you move your eye around and the spot moves too, you're good. It's back on now because of emission check in Nevada. I do notice that I tend to run hotter under full throttle. Can get way up there pretty fast.

 

[EBottema]

Sucks to see Nevada went to emission checks. I am soooooo soooo sooo suprised that California is still not testing deisels. It is funny stuff down here. Lets not allow dual sport motorcycles that get 75mpg fuel economy but no diesel testing. Don't get me wrong, i love not being tested but then again California makes no sense. It is not even worth the time trying to figure out the logic lol

 

[AMink]

Just Washoe (Reno, Sparks) and Clark (Lost Wages) need to smog. The cow counties are still part of "the old west"! I also noticed, right away, that my cool big rig sound got sucked down the tubes! I don't know why you need a cat and a muff. The cat really quiets it down!

 

[C. Harlan]

Mike- I have been running without mine for 5 years now. No problems around here. I get it inspected every year, and you would be amazed at the hp gain from the removal of that little booger. Honestly, you have nothing to worry about, unless you go to one of those rip-off state inspection depot things. All you need to do is find a little hole in the wall shop on the 'other' side of town who does inspections, and you are set!



For the record, Cats do plug up, alot sooner than 250k. It depends on the driving habits, and other factors as well. We have some trucks at work that are chugging and struggling to keep running, and all I can do is just sit there and feel sorry for the cummins on the other side of that restrictive cat. Just breaks my heart.



-Chris-

 

[Mike Ellis]

Thanks for all the info folks, may have to get one of those test pipes from Mopar

 

[Vaughn MacKenzie]

Mike, I wonder if you ever wanted to upgrade to a 4" system how "kosher" it would be to install one of the cats off an '04. 5+ truck? Should be pretty easy to get one with guys whacking 'em off during exhaust upgrades. While not original equipment at least you'd have a freer flowing system and still be doing your part on emissions control.



Vaughn

 

[EBottema]

Vaughn is right. I'm sure that 04 Cat is much freer flowing and better on performance than the 96 Cat

 

[Mike Ellis]

That's a pretty good idea. I hadn't thought about the 3rd gen cats, but I did lay under the truck and contemplate the reverse of my old Corvette system - wondered if it would make sense to use a bigger exhaust system, and split it to run through TWO cats to get better flow. If the 3rd Gen cats are bigger it would be a better fix, but I bet they charge out the wazzoo for one of those cats. Hmmmm maybe I could get a discard from one of the guys that has already hacked his off.



One thing that makes me scratch my head, is that I recall reading that the cats have to hit a certain temperature before they are functional. It might be that the exhaust system is designed to intentionally provide a bit of back pressure to keep the temps up. If so, would putting on a bigger cat just lead to more severe clogging problems if it didn't get hot enough to function?



Might be worth trying anyway...