That "3rd cat" is a straight thru resonator. Remove it and it looks like a glass pack; though probably filled w/ SS instead of fiber glass.

My stock 92' is so God damn quiet, the only way to tell the car is on is by the slight ticking of the valves. Rev it and all you hear is the intake gasping. It is unbelievable how quiet they got this thing.

 

I've heard different things from the US now. Do exhaust specs vary from California and year to year over there?

I have diagrams showing LS400 has quiet exhaust like the Japanese Soarer - same muffler layout.
I have a TV ad for US sc400 and exhaust is loud and sounds like a V8.

Manary's titanium exhaust pics show the different resonators to mine stock ones - rear mufflers look the same but someone over there said you can look straight through them - that they weren't the reflection type like my stockers.

[IMG]stockUS[/IMG]

US exhaust with Three cats, more temp sensors etc, straight through small resonators and big mufflers (straight through?)

[IMG]Japanesestock1[/IMG]
[IMG]japanesestock2[/IMG]

Japanese stock Soarer (similar to LS400).
Two cats
one straight through resonator
two middle mufflers
two rear mufflers
Doesn't have sound - doesn't sound like V8.

So what do you reckon about that diagram for the US SC400? - Is that correct and universal?

 

well that didn't work too well!

stock US:

 

Japanese stock part 1

 

part 2

 

Ahh, looks like the US LS exhaust.

That centor resonator which looks somewhat like a cat, is not a cat. You can safely remove it.

If you want to see detailed pics of it lexsc, I can take some. All of my exhaust parts are in my trunk!

 

Yes, greatly! California has much strictor emissions standards

Quote:

Manary's titanium exhaust pics show the different resonators to mine stock ones - rear mufflers look the same but someone over there said you can look straight through them - that they weren't the reflection type like my stockers.

All of my stock components are straight thru design 'cept for the 2 cats. You can even see just by shining a flashlight down the muffler tips.

Quote:

Japanese stock Soarer (similar to LS400).
Two cats
one straight through resonator
two middle mufflers
two rear mufflers
Doesn't have sound - doesn't sound like V8.

That sounds exactly like my stock SC (non calif emissions), but the middle mufflers are 6" cylindrical "can" mufflers (straingt thru design) not the offset 4.25 X 14" standard muffler design. The front resonator is also cylindrical and not shaped like a Cat converter; no shield either. And yes, sounds nothing like a V-8. Hopefully that will change. Luckilly, taking off the intake snorkel added a little V-8 woosh to the intake.

 

That stock exhaust isn't bad at all,was surprised to find all the mufflers to actually be resonators;straight through,no baffles.
I'm sure you could gain a few hp by removing one or two of them,but not a whole lot.
The intake will give you a nice note after the retaining ring for the screen inside the airflow meter is removed,and all the flat surfaces rounded off with a rotary file.That,along with the front of the airbox removed,and a thin metal duct placed just inside the new opening to get air from around the headlight via the opening under the headlight.
Gotta be the best bang for the buck,since it's improved the response more than fuel/timing adjustments,and after all,was basically free.

 

Wow, I must say I am surprised. Those first pictures definitely show a 3rd cat with small 2nd resonators. The second pictures show the SC400 exhaust that I have seen here in Texas. I guess the first are for California???

Anyway, the second picture resonators/mufflers look very similar but not quite like the LS400 layout that Peter has on Planet Soarer http://www.users.bigpond.com/pgscott...s/exhaust.jpeg

All the LS and SC exhausts I have seen do NOT have a 3rd cat but obviously there are some that do have that layout. lex400sc saw honeycomb inside his indicating he has a 3rd cat. Removing it would probably fail the car visually but I would suspect it would still pass the sniffer with ease. I would not recommend hollowing out a cat as that would make it louder but may not inprove flow and in fact could hamper flow.

I would remove EVERYthing from the primary cats back an create a better system. It should pass easily and if you have a problem you can always install the stock parts again to get your sticker.