Cat Alternatives
 

Hi everyone,
I have had an annoying noise since I have owned my 850 which appears to come from the Cat, it is like a metallic rattle that comes and goes, must be a relative of my AC since it appears to have a mind of its own.

My question is if I have it removed, what problems will I have related to the down stream O2 sensor?

Like many, I am on a budget so I have researched some aftermarket "universal" cats that are not that expensive (from 60-150 dollars), are these worth the money or should I just go "catless"?

We have no emissions laws where I live and I dont expect the car to return to CA anytime in the future :rolleyes:.

Thanks in advance for any advice :)

If the car runs fine, the metallic rattle may just be the heat shield. If the car runs poorly, the rattle may be broken pieces inside that block the exhaust flow.

Universal cats would need to be welded to the downpipe and may not save you anything in the long run.

I bought a replacement cat for $230 plus reasonable shipping from Parts Train. I'm replacing the entire exhaust on my 850 wagon. I repaired the exhaust header by welding in a replacement flex piece and picked up a muffler from a local parts store.

One alternative to a cat is to...

-- Take it off and punch out its insides with a screwdriver. :cool:

I did this with my old '94 Toyota Corolla as an alternative to getting a straight pipe custom made. This method was much, much cheaper.

Only problem is that I didn't realize cats had PLATINUM inside, which is supposedly hundreds of dollars an ounce. Had I known that, I would have kept it and looked into scrapping it.

Maybe I'll do the same to my 850....

Wonder what the new effects of the downstream o2 sensor would be after opening the cat up???

P.S. -- Just because you don't live in california doesn't mean you don't have equipment laws to abide by. I can almost guarantee you that virtually every state has a law on the books about having both a cat and muffler. It's just one of those things society expects, along with brakes, lights, signals, horns, etc.

The car does feel a tad underpowered. I was under there today and tapped around, the heat shield is fine and sounds nothing like the rattle I am used to. When I shake the Cat, it rattles :( makes the funny sound I mentioned.

As for punching out the innards, I dont know why that sounds easier said than done on this car! I think I may just have to bite the bullet and get a new one, I know you are right about regs and all that stuff...

Thanks for the help guys!

Don't sweat the regs...

The cat will still be there, and nobody's going to be inspecting its innards.

It's at least worth a shot, will get you some platinum to scrap, and will make replacing the FUSED exhaust bolts much easier if you really decide that you couldn't handle more than a week of the "excess" noise.

Okay, I'll bite, how do you punch out the innards without making a hole in the thing? it appears to be a solid piece from the downpipe and then afte rthe cat it is a long run to the muffler joint.

Ive had the noise for quite a long time, I just recently decided to do something about it.

Thanks!

Art

5/8 rebar works pretty well most of the time.

Is there a DYI procedure somewhere that I can take a look at?

Thanks!

I haven't looked at the exhaust of this car yet, but I googled an image of it... and I get various images...

- Some look like a short cat that would be much easier for this "DIY procedure".
- Others are cats that have a pipe welded on each end, which would make this a tad more difficult.

If 850s fall in this second category, then I know Advance Auto Parts [so I'm assuming the others should have this stuff too] has these "sheets" that slide over the pipes if you need to cut them yourself [which you would would obviously need to do if our exhaust falls into this second category]... with one of the bigger cut-off wheels, a sawzall, or something with a thin blade like that. (If you were cutting at the end of the pipe, to add a muffler, then the thicker blade of a grinder could be used if you cut closer to the end.)

But the idea is to use these metal, cylindrical sheets to join and brace the pipes when you put them back together. Then you just tighten down your clamps with nuts & bolts.... and you can DIY without having a welding machine. :)

I actually got these tips from a guy who came into Advance when I used to work there long ago. He got a new muffler for Christmas and wanted to take it to the muffler shop and get a straight pipe put on... but, of course the shop was closed for Christmas.... so he came in there, got all the parts. And inspired me to go home and punch my cat out my damn self. :)

Sounds like fun. When I was last down there taking a look, the down pipe widens into the Cat. The cat on my car is quite long, I dont know if this has anything to do with the fact that it was a California car or not. I was actually thinking about taking it to my local muffler guy and asking him to cut a hole in it and take out the guts, lol... I cant do the job myself, I am not well equipped for this kind of job.

Thanks for the advice and the suggestions, I will post what I end up doing :)

This is a stock converter, comes one piece with the downpipe. If you punch out the converter then you likely will have a constant CEL for catalytic converter efficiency below threshold.

Hey Frog,

Thanks for the pic, but mine does not look like that :confused: Next week when I get back down there I will take a picture and post it, maybe I am looking at the darn thing wrong? I am almost sure that this thing is unusually huge!

That sounds like an idea, provided I can get the thing out without breaking any bolts...

Well,,,, the muffler is the size of a suitcase. :confused:

lol, yes it is, I remember staring at the thing the first time I met it!

and it weighs about 900 lbs. at least it feels like it when you're under the car trying to lift it into place...