Y2K_Frenzy

I think I need a drivers side cat for my ‘00 Z28. The exhaust is stock aside from the muffler. I have a P0420, idle rpm fluctuations, and a rattle in the exhaust on that side. I think it’s breaking up and clogging. If I was able to turn off the CEL myself I would probably just hollow it out and call it a day. I’m not sure if there’s enough room after the flange to have a set of cheap universal “high flows” in, and I bet they’d probably set off a check engine light anyway. I bet I’d be looking at $500 to have just the drivers side replaced with an OEM replacement. There aren’t any tuners in my area that I’m aware of either. If mailing in an ECU for $175 was still a thing I think hollw cats for the time being would the way to go. Does anyone know a “mail order” place that’s anywhere close to that? If a tune to turn off the CEL is $500 I’d really have to think about no cats/hollow cats vs oem replacement. I’m not real wild about the no cat smell, but I could tolerate it if it were a cheap fix. To be honest I’m not really ready for a “tune,” I just don’t want to ride around with the eternal check engine light. The engine is in good shape, but the tranny is suspect and reduced tq management would probably be a death sentence.
What’s the best way to skin this cat? Scower the web for a cheap guy to send my ecu off to and hope I don’t get robbed, then gut em? Y’all know a guy? Or bite the bullet and pay a lot for one oem replacement?

RPM WS6

iTrader: (3)

I'll just leave this simple solution right here...

https://www.ws6store.com/product/98-...tors-set-of-2/

Y2K_Frenzy

I’ve heard about the simulators but I wasn’t sure if they really worked or not. I’ve tried the spark plug anti fouler o2 sensor trick before on another car and it didn’t work.
If y’all were betting men would y’all bet that I’d have a hard time unbolting the cats?
*Edit*
Post 4 says the WS6 stores simulators didn’t work for him. #4

RPM WS6

iTrader: (3)

These have always worked for me, on all different model years of LS1 F-body (including my '00 and '02 car). I've never had them NOT work, and no other tuning was required. Not sure what those other guys were dealing with.

And yes, I suspect you'll have a hard time unbolting the cats due to many years and 10s of thousands of miles of heat cycling.

Y2K_Frenzy

I see that they don’t have a pigtail to splice into. Do you have to solder the wires to the new connector pins?
And thanks.
*edit*.
Is there a bolt in ORY pipe out there for stock manifolds? I was thing maybe a new Y or seeing if I can have a guy chop off the cats and replace with a piece of pipe instead of gutting the oems. But I don’t know if I’d be able to find some one to remove cats this day and age.
I figured if I was taking them off anyway to gut them I’d rather bolt something else back in their place if I could. Or how about some bolt-in “test pipes?”

RPM WS6

iTrader: (3)

The O2 sims just plug into the O2 sensor harness, there is no soldering or splicing or anything else - just plug & play (other than possibly wanting to ziptie the O2 sensor wire out of the way, assuming you're leaving the sensor in place).

Mufflex used to make exact-fit cat bypass pipes for the stock 2000-02 Y-pipe. Those haven't been in production for a very long time, but there might be a used set somewhere on the market.

Y2K_Frenzy

Thank you sir. I heard a sound clip of what was said to be a stock exhaust with no cats and it sounded decent. I don’t think they were hollowed out cats though. Earlier I was looking and I found some “test pipes” for various cars but none for mine yet. They were all way too expensive anyway. Some were about the same or maybe more expensive as a set of long tube headers. I sure don’t want to get into long tube money just for cat removal.
Does pretty much everyone break the bolts when removing the cats? Is the possibility high that attempting to remove them in the driveway will turn into a nightmare?
Do you think these could be welded in? They’re 13” long. $40 “Test Pipe”

Y2K_Frenzy

I tried to order the sims from the WS6 store but I was having problems “checking out.” I guess I’ll have to call them Monday.

jmd

iTrader: (4)

Post up looking for used. Might get lucky for yours. It's easier to sell a car at a good price if you have a smog cert. even if the vehicle is mostly off-highway use. I got 2010 cats (totally diff. project) for a silly good price. I think the 2000-2002 are the same.

Y2K_Frenzy

I don’t think there are going to be any good used 00-‘02 cats left anymore. They were falling apart early and GM sent a letter out letting people know they extended the cat warranty to 10 years and I think 100k miles. I have the letter in the glove box the sent to the previous owner. Even if they didn’t crap out early we’re still talking about at 24 year old cat.
Do y’all think a shop could weld these in somehow? They’re 3” diameter and 11” long. I think the cat without much pipe before the flange might make it hard to get a universal set in. But maybe it can be done.


Not much room to cut & weld

CattleAc

iTrader: (7)

I've used a bunch of these and always had good luck with them...

RPM WS6

iTrader: (3)

I don't think those would fit without some creative welding.

The only "test pipes" that I know of that were made as a direct fit for the 2000-02 LS1 F-body were the Mufflex pieces, they were 409 stainless and they did fit excellent (I used them on my '00 car before I had headers). I think they were like ~$100 back then (this would have been 20+ years ago). A couple places used to sell an entire ORY pipe for the stock manifolds as well, but I never had one of those.

You'll probably have to cut the studs on the ball flange (Y-pipe) end, which isn't a big deal, but if the studs break in the manifold end that's going to be a bigger problem. That's fairly typical at the age of these cars. Most folks are pulling everything to do headers anyway, so it doesn't really matter in their case. I would soak them excessively in PB Blaster before even attempting removal (heat might help as well). Or, if you just want to hollow it out, you might be able to do that without pulling the manifold end (though it would require some creative use of flexible rods, etc.)

Y2K_Frenzy

Man getting cats or removing cats seems like it’s going to be a bit more challenging and expensive than what I’m used to. In the automotive world that I came from the cars had an H pipe and the cats were welded to the H. There was plenty of room to cut and weld so pretty much any universal cat could work. Or a piece of straight pipe could be welded in in their place. Or one could opt to bolt in an “off-road” H or X pipe (or a catted one too I suppose). I think my Camaro is the first car that I’ve had (including mundane cars) that has me wondering if a muffler shop can replace a cat without having to order an OEM style cat prior taking it to the shop. Usually I wouldn’t think twice about IF a shop can cut and weld something in. There was always a universal option that didn’t require reinventing the wheel. I think that this might be the first time that if I was to take it to a shop saying I needed new cats that they’d say, “dang, I gotta order them” instead of, it’ll be ready this afternoon.” I’m not sweating not having a bolt-in cat that I can do at home so much. But the possibility of not having a universal cut & weld option is a little frustrating. What sort of options do you think an exhaust shop has other than a direct bolt-in replacement without getting crazy expensive with fab work? Would they, could they chop off the mounting flange on the Y pipe side and weld the cat directly to the Y? Surely not everyone that has cats have bolt-in’s but maybe?

Y2K_Frenzy

You use it like you would a spark plug anti fouler?
How much are they and where do you get it?
*Edit*
I found a bunch of them online. Are any of them any better than the other? I’m not sure if they all have the same catalyst in them.
*Edit Again*
I think I found the ones that you listed. They’re $50 each though which is the same price as the o2 sims that plug into the harness. There are some $20 “mini o2 cats.” I wonder if they work as well.

lees02WS6

iTrader: (5)

Why not just cut an access hole in the existing cat, clean it out, and weld the access hole back up?

As far as keeping cats, I certainly have welded in cats that are cylindrical rather than flat, in the stock locations, which can be cheaper than the stock replacements. Not the prettiest effort I've made, but it can be done.





The three considerations I can think of for going this route

1. You're locality has strict emissions enforcement (follows Cali's CARB rules). In which case the you're jammed, and will have to buy cats that are compliant with CARB.
2. You have a visual inspection to pass
3. You just want to cut down on drone/or don't like the smell of an uncatted car

Y2K_Frenzy

I can’t weld so I’m at the mercy at a shops mercy. I’m pretty sure that they won’t gut a cat for me, plus I think that would cost more than what it’s worth. Ideally I would like a set of those cheap cylindrical, “high flow cats” welded in if it would be a cheap enough fix as far as not having a clogged cat. That is if I can aquire o2 sims or those “o2 mini-cats” that would keep the CEL off. They don’t do an exhaust “sniffer test” in my county but I’d rather not have the car-less smell and I definitely don’t want a constantcheck engine light. I had a set of those cheap cylindrical cats added to a car that didn't have cats and they did a good job at eliminating the odor. Do you think a muffler shop would have an easy enough time making a set those style cats work on the stock exhaust system without getting super expensive? I’m betting a single stock replacement would be $500-$600 parts and labor. I’m trying to stay under that to have a pair of generic “high flows” welded in. Do you think it can be done? It would stink if the high flow cats give a CEL and a sim or anti fouler device couldn’t turn it off. But if the price of the high flow cats bought and installed is cheap enough I’d be willing to take a gamble on them and a device to try and turn off the CEL.

G Atsma

I'm still trying o figure out what a "cat delima" is....
What a dilemma.....

lees02WS6

iTrader: (5)

You're over thinking it. You could google welder and the name of your town, and ask around, it doesn't have to be an exhaust shop. There are dozens within a stones throw of me. Yes, they almost certainly will replace the cat for you, outside of California and New York.

If you can get the existing flanges unbolted, any welder can quickly create a jig to hold them in the correct orientation, cut out the existing cat, weld in the new one with minimal distortion and hand it back to you. My guess is $100-$200 (time and materials) on top of the cost of the cats.

Regarding the CEL, I would do the simulators or a tune to get the CEL out, regardless of what you do about the cats. It's possible a set of high flow cats will continue to illuminate the CEL. You can replace the cats and see what happens. Goes out, great, otherwise just do the simulator or the tune.

Y2K_Frenzy

I don’t want to unbolt anything really. I don’t want to risk breaking bolts in the driveway. What I want to do is order a set of of those universal cylinderical cats and then have a shop weld them in. Will the typical cut, splice, & weld work with that style of cat with the stock 4th gen f body exhaust? Or will they tell me that there isn’t any room to cut and splice? Would they could they add a section of pipe where the oem cats were and then put the universals in further back?

Can these be made to work with the stock 4th gen exhaust w/out reinventing the wheel?

lees02WS6

iTrader: (5)

You can make that fit with reducers, i think the stock manifold flange is 2" or 2.25". A cat with the inlet/outlet size you have pictured is more effort because you need to weld on cone reducers to make it work. Just use a dial caliper to get the outside diameter of the current cat, and buy a pair of cats that matches that size. Hand the exhaust shop the cats, and ask them to replace the cats that are on there.