Exhaust Backpressure
#16
Racer
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Originally posted by lex400sc
My SC400 wasn't whisper quiet when I got on it. It was about as loud as a stock Z28 actually.
JBrady, so you're saying the third cat is not legally considered a cat at all? So if I had it removed and smogged, then my car would pass inspection? I had the outlet of the "third cat" cut off and saw an intricate layer of honeycomb mesh inside. To the best of my knowledge, that's what a catalytic convertor has inside as well.
My SC400 wasn't whisper quiet when I got on it. It was about as loud as a stock Z28 actually.
JBrady, so you're saying the third cat is not legally considered a cat at all? So if I had it removed and smogged, then my car would pass inspection? I had the outlet of the "third cat" cut off and saw an intricate layer of honeycomb mesh inside. To the best of my knowledge, that's what a catalytic convertor has inside as well.
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.
#17
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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?
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?
#22
Racer
iTrader: (3)
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Originally posted by UZZ32
I've heard different things from the US now. Do exhaust specs vary from California and year to year over there?
I've heard different things from the US now. Do exhaust specs vary from California and year to year over there?
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.
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.
Two cats
one straight through resonator
two middle mufflers
two rear mufflers
Doesn't have sound - doesn't sound like V8.
#23
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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.
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.
#24
Lexus Champion
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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.
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.
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