sonyman

Obviously you haven't read them all.

skperformance

iTrader: (6)

That scan shows a twc which I have no clue what it stands for. The only Lexus i know with 3 cats is the IS300 with 2 on the header and one down stream.
It really is not a 3rd cat it is just a resonator on the LS contrary to what you may have been told.

skperformance

iTrader: (6)

Just to prove to you it is not a cat and is a resonator. All cats have o2 sensors before and after each one to make sure they are working. There is no o2 after that in that picture or any LS i have seen nor my OEM Lexus manuals. Even the IS300 has another useless sensor after the 3rd cat to make sure it is working.

sonyman

It IS a cat. I've looked under my LS to verify. TWC= Three-way catalytic converter.

turbosix

https://www.clublexus.com/gallery/da..._underbody.jpg

doesnt look like a cat to me.

skperformance

iTrader: (6)

Looking under a car is no way to tell if you have a cat or not. I already pulled mine apart as it is cut from my car and i can see right through it ..It could be that some dumb *** who owned the car before you went and damaged the old pipe and thought it was a cat so he welded one onto the car instead of a muffler.
You really have to give it up though as the LS400 never had 3 cats from the factory.
You may have one or think you do but no one else does. And that diagram means nothing.
And just to prove it beyond reasonable doubt for the last and final time.
The replacement front pipe attached to the resonator from the dealer is
$250 (pn# 17410-50220) . While one cat is $1000 ( pn# 18450-50010 )with no piping ! Do you think they would sell so much curved pipe for so cheap with a resonator with precious metals like platinum from Toyota for so cheap.

sonyman

I looked underneath my car to verify that it looked like the diagram. As shown in the picture on the first page, the resonator is shaped like a cylinder, whereas the 3rd cat is not. Go to your dealer and look at the parts diagrams if you wish. I happen to work at Lexus, so I will personally take this pursuit. From my experience, Lexus uses different exhaust configurations on different models to meet the emissions requirements of local governments, i.e., California cars have different emissions controls than Virginia cars. As for my exhaust being modified, that's a no-no. Judging from the diagram, the 3rd cat is different from the front TWC's, and a frontal TWC will not bolt up in the location of the rear TWC. That diagram does indeed mean something, considering it came directly from the horse's mouth. However, I feel no need to prove myself to you, and therefore, honestly don't give a **** if you don't believe me. TWC = three way catalyst/catalytic converter. Have a good day.

sonyman

That's because it isn't in that picture. Different cars, perhaps to conform to local emissions requirements, may or may not have a 3rd cat in place of a resonator.

ewenpg

I ll prob go with the Magnaflows but Ill ask about the Borla and HKS and see what he says. I want it to sound good but not tooooo loud and hoping that the engine will relax a bit with a more open muffler. Just taking the resonators and eliminating that nasty bend it had to do to go it the resonators (ugly!), made the engine relax quite nicely!
Oh and just a silly question: How do you put a pic in your messages?
Ewen

PureDrifter

iTrader: (10)

really, well i had a 95 and have a 99 and an 00 AND i live in SoCal, the most ****-ish state on emissions regulations. Also, iirc Toyota/Lexus ONLY makes emissions/state-cars for CA, no other state unless that state follows ALL of CA's smog rules.

the center box in my exhaust, its a resonator.

2 of my friends have had exhausts MADE for 1LSs (ie pre-95) and same thing applies.

if u still dont believe me give me a couple weeks and i will have the entire center section cut out and show you that its a resonator.

skperformance

iTrader: (6)

Diagram have typo's ,what do you do at Toyota?
If you work at Toyota then look up on your own Toyota EPC and check the prices and names. I have it right in front of me to confirm this as well as the Lexus manuals to go on.

It is agreed that California has separate emission limits for cars. You are in North Carolina which is no where near as stringent as CALI and i am no where near both of you.
Here is the problem if you say yours looks similar .
Why does it not have an o2 after it.
Why is the Toyota EPC (electronic parts counter ) not calling it a converter
Why is the price so cheap.
Why do you belive it has too look a certain way ?
Why are you the only one ever to have one.

A cat and resonator look the same they both can be different shapes and sizes but one has a honey comb center and the other is hollow.

Your just being stubborn in light of others having way more knowledge than you and admitting it. Pure knows his **** as i hope i do as well . BTW what you are looking at when you see the resonator is a heat shield which can be slipped over either one . So come on now and atleast admit you might not be right.

sonyman

I work at Lexus, not Toyota. I'm not a tech, but I have access to all the computer records, personnel, etc, so it's easy for me verify that diagram. I'm familiar with diagrams having typos, but this is a picture. My car is a California car. It has a different ECM, EGR, etc. The part number that you found in the computer is obviously for cars with a resonator in place of a 3rd cat. Also, I am not being stubborn in light of others having "more" knowledge. I'm not admitting anything because there is nothing to admit. If you return to my OP, I said that it is not a rule of thumb to have 2 cats. You and PD seem to think that I said that all LS400's have 3 cats, which is obviously not the case. I also don't believe it has to look a certain way. I am saying that in exhaust configuration A, with a center resonator, it enters straight and leaves straight. The configuration with a center cat enters and exits with an offset, as shown in the diagram. I honestly don't know why you and PD feel the need to prove that they all have 2 cats, because it isn't the case. And PD, cutting your exhaust proves nothing. It only shows that your car has 2 cats- it says nothing about the thousands of other LS400's on the road that may have 2 OR 3. As to the O2 issue, you and both know well that the front O2 sensors do 90% of the work, and the sub O2's are almost useless. Having another set would be moot. Honestly, you're looking at a circle and calling it a square. I posted an undoctored image of the center TWC and you're saying that an image, not text, is a typo. I'll have part numbers tomorrow for the exhaust section with TWC, so be prepared to eat your words.

pito

greenvy2k

i work at lexus and have never seen that third cat.

CK6Speed

iTrader: (1)

Although I'm not a moderator in the LS forum, I am one so I suggest everyone just take a deep breathe and relax. Let's not get personal. Tomorrow we will see if any LS has a 3rd cat and exactly which years it came on if it did. Or, we will see that they all have a resonator there. Either way, no sense arguing over it anymore

Hopefully tomorrow when sonyman gets his info one way or the other we can get back to talking about modifying or getting after market exhausts systems for the LS and not turn this in to a "I told you so" rant.

My two cents, I'm no expert but I have never seen a cat without a 02 sensor after it on an OBD2 car. But, obviously I have only seen a limited number of cars so I could be wrong