Gutting cat?(3sfe) - Toyota Nation Forum : Toyota Car and Truck Forums

stricular · 08-08-2007, 07:46 PM

I am looking at doing some exhaust repair, so I figured i would ask about this. Anybody gutted their stock cat? Or maybe fabbed up a decat? I have about 215k on her now, so I would bet it's clogged at least partially. How would I go about doing something like this? Just start jabbing the screens with a screwdriver?

Any input would be appreciated. Thanks.

Disclaimer:of course if i did dispense with the stock cat, i would certainly be sure to add an aftermarket one under the car somewhere

***HomeGrown*** · 08-08-2007, 08:54 PM

Gutting the cat is easy (relatively) on these cars. IvanHoe did a good write-up on how to do this. I don't think he started the thread, but his explanation was in the thread. I'll see if I can dig it up for you.

I disconnected the 3 bolts at the bottom of the exhaust manifold, took out the o2 sensor (to keep it from getting damaged), then used about a 3/4" 2-flute wood boring bit and went to town on it. Did both my cars. When I did my '91, it wasn't even jacked up, but it does make it a lot easier.

EDIT: Found the thread here

stricular · 08-08-2007, 10:01 PM

Many thanks!

So did you notice any perceivable difference in power?

fredk · 08-08-2007, 10:08 PM

a little louder

scribby · 08-08-2007, 11:37 PM

I noticed a little power and slightly less fuel consumption when I did mine. Only downside is ever since I gutted my cat I get this annoying whisleing sound when going over 3,000RPM. I'm going to try and solve this soon by putting a straight pipe inside the cat.

***HomeGrown*** · 08-09-2007, 12:10 PM

The slightly louder sound was more noticable than any power or mpg increase.

jarrett5681 · 08-09-2007, 12:19 PM

http://toyotanation.com/forum/t171715.html

Here is the write up IvanHoe did.

stricular · 08-10-2007, 01:01 AM

I want to go ahead and do this, but one thing is stopping me: I cant seem to find an o2 sensor gasket anywhere. i know toyota sells them but they want like upwards of ten dollars for it, which to me is a rip.

Does anybody know where they sell them retail? I know the bosch relacement sensors come with them, but I really dont need to replace it, just the gasket. WTF gives? It almost makes me wish I worked at a parts store, so i could just steal one.

On a related note, I had posted my '90 parts car on craigslist, and the only two replies I got were from people who wanted to buy the stock cats. Apparently the recycling of these magic cans has become a lucrative business, due to their precious metal content.

I did a bit of searching about the legality of selling someone a cat, since I know that junkyards arent supposed to sell them, and that it is illegal for a shop to install a used one.

I found a few news stories which reported the increasing theft of cats. I guess now thieves will actually get under trucks and cut them out. They seem to sell for pretty good scratch(~$45 each).

I am not suggesting that you start stealing cats, far from it. What I am getting at is, these recyclers arent in it for the cast iron or galvanized steel, they want whats inside the cat. What are the odds they would buy the contents of a gutted cat?

I mean why let it go to the trash if its worth money?

IvanHoe · 08-10-2007, 03:29 AM

thanx for posting the link to my write-up on it....you guys are great!

about the gasket....I dont have a clue, when I did my cat, coincidentially I had replaced the O2 sensor a week prior, so the gasket was new.....which is probably a good idea for you to do anyways.....my MPG went up with the fresh O2 sensor!