kevin444

Ok im in california.

Check this out, I got 2 cats under my runner its a 00. My 98 4cyl only had 1. Since i ordered a high flow cat originally for the old runner.

Im planning to yank off both of them. ANd just bolt on a high flow cat. You think ill still be able to pass smog? Cuz man these 4runners have potential!

rimpainter.com

As long as you are at operating temp, you should pass smog. The first cat is to reduce cold start emissions. Personally, I really do not think you are going to see as big of a HP gain as you might imagine.

Keep in mind that tampering with working emission control devices is a federal offense...so you might have a hard time finding a welder for it.

Mod away though.

AgRunner06

I thought it didn't matter as long as the vehicle has over 50K or 55K miles (can't remember which). I replaced my OEM cat that was working fine but I had 130K miles at the time.

jimbo74

there is a lot of legal stuff that most muffler shops wotn even touch.... i think only a state approved place can even touch cats now adays... the local muffler shop i go to has a sign that says dont even ask us to touch the cat, unless you feel like paying the $2500 fine....

rimpainter.com

I have read the legal notice regarding cats posted inside most major muffler chains, and it is pretty specific about not tampering with a working device. I read this notice many years ago, so the rules may have changed slightly, but I doubt it. Let me know if you find anything out.

I guess if you took a hammer and ruined the stock cat a muffler shop would weld on the new high flow cat.

But you know, in this case I think it would be a crime to remove one of two cats. But, don't quote me on that. That is a very good question.

kevin444

Yeah. It boggles me but its not fair to put 2 of them on a 4runner.

CoedNaked

I have heard of guys who will have their cat's on for "smog" (up here in British Columbia Canada we call it "Air Care" - I prefer to call it "Cash Cow") and then remove them for performance, and then reweld them back in for smog. With what is essentially a new cat they pass pretty much everytime supposedly (although there are other reasons you could fail too- I said just about).

Jason B

A buddy on mine with a M3 removed his cat and replaced it with a straight pipe. Gained 15 rwhp! The 4Runner is no M3, but it made a huge difference on his.