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See that’s what I heard too but from the diagrams and Lexus parts list that does not seem to be true, according to the list of parts the ones attached the exhaust manifolds are the catalytic converters. The other things that are further down the exhaust pipe is something else I guess , and it’s not described as something else because it’s not sold on its own.
hopefully someone else who has physically dealt with those things can tell you.
There are 2 cats that are part of the exhaust manifold. They are attached to the exhaust piping which have resonators on both sides. The exhaust piping are attached to the mufflers.
What he said.
The cats are made attached to the head pipes then you have two mid pipe resonators and all the way on back just in front of the bumper are two gigantic mufflers that weigh about 20lbs each. The head pipes are actually made just like headers and no cast manifold per-say. Nice for performance.
I found it strange that they made the exhaust this way as in most instances the resonators are behind the mufflers. And there is no tail pipe behind the muffler, it just comes out those ports in back. But it works and its sure quiet.
Also has to be the easiest exhaust to work on due that all connections are two bolt flat flanges with gaskets. You can replace as needed like in a modular fashion..If a bolt breaks, no big deal. They are just standard grade 5 nuts and bolts easily replaced.
I found that my Toyota Sienna exhaust is made the same way with two bolt flat flanges.
If I understand correctly, catalytic converters work with the heat from the exhaust headers. So only one for each bank. This would be any brand of car.
Not necessarily. Most v6 and v8 engines will have at least two.They are generally positioned so that they are close to the engine to maximize heat and the catalyzing of the exhaust. You will also usually have four O2 sensors. One upstream and the other downstream of the converters. Older models only use one O2 sensor in the downstream position.
Some cars will have four and I think that to be unnecessary with the computer systems in cars these days.
It's four. If you don't believe me - allow me some time to fetch you all a diagram here she blows. 2 before downstream O2s and two after (Two Way Cat).
As many times Ive been under the car I never saw those other two converters. Just wasn't in the right place I guess.
Thats going to suck if all of them need replaced. I had thought there were only two as others stated too.
Makes sense though as my Toyota Sienna has three converters. One on each bank and a common one after the two into one pipe.
I threw in a pic of the drivers side head pipe/converter.
Admittedly, I'm not up on the tweaks that engineers do to modern cars. It's pretty amazing how engines are smaller, yet produce more power, less pollution and better fuel economy.
It's four. If you don't believe me - allow me some time to fetch you all a diagram here she blows. 2 before downstream O2s and two after (Two Way Cat).
02-06-23, 03:04 PM
