4Runner4Christ

I have a dual cat exhaust system that I am looking at replacing with two Magnaflow cats & Magnaflow muffler for about $250 total for parts, not bad. I took my rig to the exhaust shop I use & we put it up on the hoist & took a gander to see how difficult this was going to be. He was concerned about cutting out that front cat & welding in the new one. He said because of the angle of the pipe where the O2 sensor is and its close proximity to that front cat will make it very difficult. Has anyone else run into this problem? What did you do? Did you have to end up buying a new pipe that comes down from the engine to that front cat? Thanks for your input!

gwhayduke

What would Christ do?

4Runner4Christ

He would die on the cross to pay the price for the sins of mankind, but that does not help me out much with my exhaust question.

Any other input would be great!

kevin444

You can.. Have a true dual exhuast. But it may be quite complicated. So each of the headers runners have its own unique cat straight piping all the way down with a cat and only have 1 sensor on one side? Its only a suggestion.

4Runner4Christ

Thanks for the suggestion. I did look at the TRD complete header/exhaust system, but it was WAY high priced and I really didnt want to go with headers.

gwhayduke

Nope.
He'd be pretty satisfied with the burro he had...maybe give'r a bath, shine her up and give the extra money to someone with a bigger need.

Dual exhaust is pure vanity...No real function on our little V6's. Plus you're gonna have to route it right by the gas tank...Not smart. Or route it to one side, then the other to avoid the gas tank. It doesn't take a rocket scientist to figure this out.

And if your gonna hold yourself up to us as a Christian, at least act the part. Ya can talk the talk, but you don't walk the walk. Amen.

4Runner4Christ

Duke, for someone who knows zero about me, or the many things I do to walk the walk, that's an undeserving slam. But I'll forgive that, and turn the other cheek. Now, about that darned check engine light that points to a failed cat that could possibly cause further damage if not addressed...

gwhayduke

Then replace the cat with a stock cat and call it a day. Order it online from a discount Toyota parts dealer and save a bundle over your local dealer or get one from a salvage yard. If you do a little research using the search function regarding cats, you'll find that many who have replaced them found no difference between the high flow and their stock cat. Car and Driver Magazine found that back in the 80's. Cats are pretty efficient and your 4Runner is tuned for a certain amount of back pressure. As witnessed by a number of self-centered bozos on here who have gutted their cat and found that their performance suffered.

Cats also rarely go bad. I question what code is telling you that you have a bad cat. Pull the engine codes. Do a search on 3rd gen engine codes or 3.4 engine codes. Post back.

4Runner4Christ

Actually I have already done my research. This is what the dealer said about the check engine light: "The scan found code po-420, catalyst system efficiency below threshold. Truck needs catalytic converter and both O2 sensors replaced. Total cost $1687.20." Other forum members have confirmed this. I did not want to spend that kind of money, that is why I am looking at aftermarket stuff, and if I want to do a bit more while its tore apart I might just do that. My search on this & other forums did not result in finding an answer to my origional question, thus I started this thread. If anyone has any input on my origional question it would be greatly appreciated!

alltrac165

I take it your system isn't like this?
http://www.catalyticonverters.com/TO...R90239699.html
I guess there must be two ways to get the 99 then, with one or two cats. Wonder why.
I haven't ever seen the dual cat set-up, wish I could help. Are you certain you can't use one 3 way cat? Or is this some 991/2 change in the exhaust?

Oh, and Hayduke, what's up with the, um, antagonistic posts? You sound pretty salty there dude.

Incidentally, in regards to "High Flow" cats, they are pretty much all of the same design these days. Originally, cats used a pellet type medium and were quite restrictive. At some point they began changing over to a honeycomb substrate that flowed much better. These were labelled "High Flow". Since every cat out there is a honeycomb nowadays, they are all "High Flow". However, there are a couple companies such as Random Technologies making cats with a more open substrate but using higher levels of precious metals and a more smoothly shaped canister. These flow a bit better than the stock replacements, but cost LOTS more. You can get good results by putting more gradual entry and exit cones on your stock cat to reduce turbulance there. That's proven. Any quality cat is going to work about the same, stock or "High Flow" as Hayduke said, I just wanted to point out why for those who care.

4Runner4Christ

Bob,

Thanks for the great reply! The link you provided is one piece I definitely need since patching in an aftermarket cat seems pretty tricky. I think I will go with the solution you provided in that other thread and set my rig up the way your's is. thanks again