Catalytic convertor removal

[badlieutenant]

Anyone have any experience getting rid of the cats by replacing the entire exhaust with someone more free flowing and throaty?

My only concern is the four O2 sensors. I don't want to throw codes.

I recently got a P0421 and a P0152

Both seem to have something to do with either the cats or the O2 sensors. I doubt it's the cats and an more leaning towards the shitty aftermarket sensors.

Either way, I'd like to lose all that nonsense but not throw codes.

 

[Chris]

Anyone have any experience getting rid of the cats by replacing the entire exhaust with someone more free flowing and throaty?

My only concern is the four O2 sensors. I don't want to throw codes.

I recently got a P0421 and a P0152

Both seem to have something to do with either the cats or the O2 sensors. I doubt it's the cats and an more leaning towards the shitty aftermarket sensors.

Either way, I'd like to lose all that nonsense but not throw codes.

There's no way to get rid of the catalytic converter's without throwing codes. Trust me I've looked into this extensively. The only way you could get by doing this is if you lived in a place that didn't require you to pass omissions. However even if that was the case and you did remove your cats your engine wouldn't run very good since the computer expects the cats to be there.

You're probably right though the codes most likely have something to do with O2 sensors and not the cats.

 

[Jerry Bransford]

Agreed, your engine computer is smart, it will notice the missing cat and will give you a permanent CEL and code.

 

[badlieutenant]

Booooo

 

[Chris]

Yeah, it sucks! Engines these days need cats to function properly. Without them they'll run like crap.

The best thing you can do is just get new sensors and make sure your cats are good.

 

[badlieutenant]

Yeah, it sucks! Engines these days need cats to function properly. Without them they'll run like crap.

The best thing you can do is just get new sensors and make sure your cats are good.

Any pointers on an aftermarket exhaust system w/ cats and spots for the factory O2 sensors? I had found a full system that replaces the OEM for about $400. I want something that'll open it up some and give me a better sound to boot.

 

[AOR]

http://bankspower.com/app/index/7#

https://www.magnaflow.com/products?partNumber=458027

https://www.magnaflow.com/products?partNumber=16389

 

[UPJOHN]

When i first got my 97 it was missing the gasket between the manifold and exhaust pipe. The flange on the exhaust pipe was rusted through so I changed the exhaust pipe and gasket. The upstream 02 sensor was also rusted and broke when I tried to change it so I replaced it. The P.O. replaced the catalytic converter with a straight pipe with a bung for the downstream 02 sensor. My check engine light stays on because I don't have a converter but I've heard that a spacer screwed into the bung for the downstream 02 sensor, putting the sensor further away from direct exhaust will fool the computer to think the converter is still there.
My TJ does run well, even with the CEL. on, and so far we don't get emission tested here in the U.P.

 

[Chris]

've heard that a spacer screwed into the bung for the downstream 02 sensor, putting the sensor further away from direct exhaust will fool the computer to think the converter is still there.

I've heard this too, but I'm not sure if it's an old wives tail, or if there's any truth to it. It's easy enough to do, so if you get a chance, please do try it and let us know!

You're lucky there's no emission testing where you live.

 

[billiebob]

Anyone have any experience getting rid of the cats by replacing the entire exhaust with someone more free flowing and throaty?

Why mess with the factory systems. They work. Free flow is only needed for high rpm/horsepower. Some restriction works to help develop torque... which we need off road. I grew up in the '70s and learned fast high rpm horsepower is great on the drag strip... not so great... actually terrible off road in a 4x4.

 

[UPJOHN]

I've heard this too, but I'm not sure if it's an old wives tail, or if there's any truth to it. It's easy enough to do, so if you get a chance, please do try it and let us know!

You're lucky there's no emission testing where you live.

I would have tried this already, but pipe is welded in and the bung right on top and there isn't enough room between the body and the pipe to do it. I don't have a welder, and if I pay an exhaust shop to do the job it might cost the same as an aftermarket converter.
A spark plug anti fouler is what I'm told does the trick.

 

[UPJOHN]

Why mess with the factory systems. They work. Free flow is only needed for high rpm/horsepower. Some restriction works to help develop torque... which we need off road. I grew up in the '70s and learned fast high rpm horsepower is great on the drag strip... not so great... actually terrible off road in a 4x4.

The converter was missing when I bought my TJ.
My current '97 seems to have more pep than my '04 or previous '97 had. My first '97 was a 4 cyl though.

 

[badlieutenant]

I would have tried this already, but pipe is welded in and the bung right on top and there isn't enough room between the body and the pipe to do it. I don't have a welder, and if I pay an exhaust shop to do the job it might cost the same as an aftermarket converter.
A spark plug anti fouler is what I'm told does the trick.

The O2 sensor hooked into a drilled out anti-fouler works

Heh.

 

[UPJOHN]

I think it was 1975 when catalytic converters were put on cars and parts stores were selling converter test pipes a few years later to replace (TEST)the converter. Well, in 1980 I had a '77 Mustang II V6 Mach1. It was a gutless wanabee, so thinking I'd up the HP I installed a test pipe and straight through muffler. It sounded ricer before there were ricers, and every time I let off the gas it blew flames out of the tail pipe. I had to put the cc back on.
If my TJ came with a catalyc converter it would still be on it.

 

[StG58]

Cat removal? I usually use a .223 and a burlap sack. Oh. Catalytic converter removal. Most of the current cats are not a hit on performance so removing one doesn't buy you much.

 

[k7nut]

BRAND new to this forum, but this is why I wanted to join, to learn from others that have already gone down this road(whatever road it may be).
My '97 has a loud rattle on acceleration and certain idle speeds, it sounded like a heat shield, but once I crawled under it, I found it was inside the Cat. I was wondering the same thing...can I delete the Cat, since I have no DEQ regs? I guess it's not such a good idea I suppose?

 

[KCsTJ]

BRAND new to this forum, but this is why I wanted to join, to learn from others that have already gone down this road(whatever road it may be).
My '97 has a loud rattle on acceleration and certain idle speeds, it sounded like a heat shield, but once I crawled under it, I found it was inside the Cat. I was wondering the same thing...can I delete the Cat, since I have no DEQ regs? I guess it's not such a good idea I suppose?

It's a good idea, if you can fake out the PCM by bypassing the cat. And I'm not smart enough to do that.
I love the idea, cuz in 4 yrs my TJ will turn 25 which means it will not be subject to all the emissions garbage

 

[59 wagon man]

walker dynomax is on sale for about $110 from summit definitely increases the sound in a good way and no codes

 

[AvocadosGuac]

BRAND new to this forum, but this is why I wanted to join, to learn from others that have already gone down this road(whatever road it may be).
My '97 has a loud rattle on acceleration and certain idle speeds, it sounded like a heat shield, but once I crawled under it, I found it was inside the Cat. I was wondering the same thing...can I delete the Cat, since I have no DEQ regs? I guess it's not such a good idea I suppose?

I purchased a manifold -cat pipe+ cat for approx $250 CAD... They can be had for cheap. If you're going that route, plan on new O2's, mine melted with the amount of heat they needed to try and reuse them...

 

[05 Blue Unlimited]

I think you should do it...