Getting Rid Of The Cat

[backwoods lex]

I just got my yearly inspection, and I am thinking about punching the cat since it is damaged. It makes a rattle noise whenever I rev the engine. But I have a few questions:

1. How much power will I get from it?

2. Will the sound be horrible?

3. How would I do it? Looking underneath, the last bolting connection I see is just before the converter. I guess just take it off, poke the cat with a steel rod, and shake out the debris? Is that right?

4. Will is set off my CEL or mess up the oxygen sensors?

The car is at 100K miles. Thanks for any help guys.

[Proteus503]

1. How much power will I get from it?

Not enough to be worth the effort... unless you've installed a turbocharger / supercharger.

2. Will the sound be horrible?

Depends on what your definition of "horrible" is, but your exhaust will be much louder

3. How would I do it? Looking underneath, the last bolting connection I see is just before the converter. I guess just take it off, poke the cat with a steel rod, and shake out the debris? Is that right?

Good luck, that honeycomb material is pretty tough. I've heard that the best way is to pour gasoline into the honeycomb and burn it to a crisp, then hack it all out with a prybar & hammer. Be sure to reinstall the cat with new gaskets.

4. Will is set off my CEL or mess up the oxygen sensors?

It will probably set off a CEL for "ineffective catalitic" or something to that nature... but it shouldnt mess with your air/fuel ratio or "mess up" your oxygen sensors.

Rather than ruining a decent OEM catalitic converter, I would suggest that you make a "test-pipe"... basically a piece of pipe to replace the cat with. Cut two matching flanges, and the proper length & size pipe, weld it all together, get yourself some new gaskets, and simply replace the cat with the test pipe. When inspection time comes around, bolt up the cat, inspect, pass, then reinstall test pipe.

If you send me your cat as a template, or some really accurate blueprints, I'll make one for $100 (shipping included in lower 48 states). FOR RACING USE ONLY! :cough: :cough: :whistles:

[Toysrme]

1) 5-10 peakhorsepower. Depends on the condition it's in.

2) The sound will not change.

3) Busting out a cat is... Extremely difficult for the good cats Lexus/Toyota uses. It's best to just cut the flanges off it (Or make new flanges) and weld a striaght pipe in. (Commonly reffered to as a "test pipe".)

4) It depends on the year, and emessions package you have. If you have a '94+ (You have a 2000) then yes, you will set off a CEL. You will have to simulate the o2 voltage (0.45v) to trick it.

It can be worth it. The effort involved in busting out a descent big cat like we have is annoying.

I suggest building, or buying a y-pipe & having the cat removed at that time & install an o2 simulator. Or get on ebay & buy one of those "high flow" cats for $20-30usd.

That be worth a good 20 peak hp. 15 past 4500rpm.

[monarch]

On another Toyota forum, the owner of a 1990 V6 4Runner did some timed 0-80 MPH runs with and without the factory cat installed. There was no improvement in the 0 - 80 MPH times with the cat removed so the owner put it back on. My understanding is that the factory original cats installed on Toyota s built since the mid-late 1980's are not significantly restrictive unless they become damaged internally from overheating. Owner failure to keep up with engine tune ups and other routine preventive maintenance is what causes the engine to generate high levels of emissions which in turn tends to overheat the cat.

[Proteus503]

Yikes! Need a good TIG welder? Lemme know if I can help! I weld & fabricate for a living... mostly TIG and some MIG, stainless steel, 304, 308, and 316 certified, all positions, plate and pipe.

[Toysrme]

Na, I taught myself to weld on a cheap wire feed welder by sawzalling my cat apart & putting it back together. I'm much, much better now.

If I were gonna buy a TIG, I'd buy the Harbor Freight TIG.

I doubt you can sell me a working TIG, torch, rods & gas for sub $500. If you can, I'm all about it tho!

Even if it's used.

Odds are that I'm gonna buy that TIG & a new 4*6 bandsaw in the next 2-3 weeks. I'm atleast buying a bandsaw. Maybe some gas tanks & make a MIG. But I'd rather have a TIG... <Shameless plug> I'm likely returbo'ing again & will need to make some headers to do what I want to do. Maybe make a Y-Pipe, or two. Maybe make some headers + y-pipes (Tho I've never liked the performance gains from headers). I've had a Camry buddy that's been riding me for a year to make him a set so...

Using an old miter saw as a chop saw is getting rather annoying. It's bandsaw time.

[backwoods lex]

Thanks for all of the tips guys. I really appreciate it. I guess the best and cheapest thing to do would be to get the high flow cat and have it welded in there. I can't say enough how helpful LOC has been to me. From reading other post, it looks like lexus would have charged me about $1K for the repair. Owning a lexus is truly nice, but knowing that you will have help with any problems makes it all the better. Thanks again.

[Toysrme]

Good choice!

If you've got $250-350 to spare Get a new Y-pipe made (That doesn't restrict the exhaust) & just have them weld the cat straight to that.