I have a problem....my cat is cracked at the flanges around the gasket...I have a 90 v6 4runner btw....and I want to know what effect it would have if I removed it all together and put a straight pipe in there?? I don't have to worry about air care where I live so thats one problem down....What I want to know is what would be my problems in doing this? Will the exhaust get annoyingly loud? Will my gas milage take a hit or improve? Will my O2 sensor act up? I only seen one O2 sensor and its in front of the cat. Well hope you guys can give me some advise....I am not looking forward to the cost of a new cat and fixing the flange on the down pipe. I think this will run up the cost of the fix at least by 2. Thanks

 

Yes, it will be louder. You will lose your much needed low-end torque. You might experience worse gas mileage. It will spew poisonuous fumes into the air. Don't do it.

I just picked up a Car Sound (Magnaflow) cat on ebay for $55 with free shipping. Your size is most likely 2.25", but don't quote me on that. Total cost of the Car Sound cat installed should be under $100 installed.

Try a search on ebay, you'll find it.

 

same here don't do it....and everybody should worry about the quality of the air

 

I don't know about the torque or mileage, but I do know it will be louder and certainly won't help air quailty.

I agree with Christian - buy a cat, put it in, enjoy life.

 

I believe it is federal law to have one if your vehicle originaly came with one. Huge fines and possible prison time if you get caught without one.

 

Meow listen up. Meow this this has been brought up thewnty thousand times including once by myself. Meow if my memory serves meow right it is illegal to do so, it stinks to high hell in the rig, and is bad for the planet. So meow before you get huffy puffy and ask why I keep saying meow go watch super troopers and you will understand why I am saying meow.

 

"Are you saying meow to me?"
"Meow? Do I look like a cat to you boy? Do you see me chasing mice? I am drinking milk from a saucer boy? Am I jumping around from tree to tree all nimbly bimbly?"



I love that movie... so many clasic lines.

 

Hey yama don't put in a straight pipe you won't have enough backpressure and your truck will run like ˟˟˟˟e to say nothing of failing your next emissions test. replace it with a free flow type cat you'll get better performance then the stock one and still be legal. If you really want to go nuts replace the exhaust with a 3" type from just just behind the manifold back including the cat and a performance muffler. I just had this done on my truck I've got gobs more power and am getting 20+ more kms to the tank. And it sounds nastier too hope this helps Aviator

 

Thanks for the input. I live in a place where you don't need to get regular testing done but I just wanted to make sure it wouldn't be bad for performance. Not to worried about the bad gases part....I mean I do drive a SUV?? But I think I will try and find a new cat, just don't have much of a selectioin up here in Northern BC Canada... wish it was easier to order parts from ebay in the USA....Thanks again to all who replied

 

ok thats fine it wont have to be tested.. but you missed the point of others threads so i will try to clear it up... its going to make the truck run worse, you will get worse mileage, it may trigger a CEL, it will pollute the air more releasing more greenhouse gasses.....

from an all around standpoint thats not good!

 

yes, it's a violation of federal law to remove the cat, but it will NOT make the truck stink inside, reduce mileage, trigger the cel, of hurt the power of your engine.

 

Federal laws dont apply in Canada, BTW. I agree with everyone else, just keep it on.

 

actually it will..... there are tons of facts to support that

also as its against federal law meaning US DOT to remove it, you better check, CANADA has a similar set of rules almost exactly equivalent to the US Standard

 

LoL where do you get your info to back up what you said? Truck? maybe not. 4runner? yes it will especially when that back window is rolled down. I would know as would another friend that straight piped a cat. A cat catches the gasses and does whatever it does with them. Without it you get a straight dose of nasty stank. I do not think it would kill the GM either but it may being one would press on the go pedal in thought of how much more power they may have. Trigger the cel? maybe on a newer rig. it could hurt the power if you stuck a 4" pipe in place of it.

 

get a new one. i dont care if you wont be alive in 200 hundred yrs to breathe the dirty air but protect the planet while you can. we all gotta breathe it in. no fun.

 

I agree get one of the Magna Flow high flow cats that the company Car Sound puts out on Ebay. I paid maybe $40 for mine and the only difference from no cat to high flow cat is safe for the envir. and no stank.

 

First hand experience.

The cat was removed from my current truck by a previous owner. I drive with my rear window down a lot, and I have no fumes.

I've owned several K-5 Blazers which were fuel injected w/o converters, and neither of them had exhaust smells enter the cab with the rear window down. Unburnt fuel? How about a tune up.

 

its ok.. there are liek 20 peopel saying its bad... and this guy dsaying its not...


of course... beleive the 1 person who knows well jsut that.....

 

jimwhatever74, I didn't say it wasn't bad to remove a converter, Maybe you should re-read my posts.

I was just stating some facts. I wouldnt remove a functioning converter, and I never have.

 

At low speeds, with the rear window completely down, exhaust does come in my rear window. I don't recall having tried it at high speeds.

The catalytic converter catalyzes or "re-burns" the unburned hydrocarbons that are exhausted from the engine. Having started my wrenching on some classic old cars without cats, I can tell you, I much prefer cat equipped vehicles. Nothing stinks like a car without a cat.

Your 4Runner is equipped with electronic fuel injection with an ECU that monitors engine performance via various probes. It was programmed at the factory for performance with all pollution control equipment installed. Changing any of this equipment alters the performance of your engine, sometimes better, sometimes worse.

Several guys on the board have reported worse performance on the 3.0 V6 running straight pipes. Many, if not most, went back to cats. Do a search and you'll find many posts on the subject.

Since you want to wrench your 4Runner, consider this an opportunity to do a custom 2.25", stainless steel, manifold back exhaust with a Magnaflow cat and a Magnaflow muffler. It would be sound great, look great, earn the respect of members of this board and not incur the wrath of other people behind you who have to breathe your exhaust.

Cost is the factor you say? Nobody ever said responsible automobile ownership is cheap. Quite the opposite...it's pretty damn expensive. But if you can't afford it, TREK makes some very nice bicycles that are much cheaper to operate.