Ehxuast Fins, what are they good for?
#1
Wrkn Toyota, Rootn Wankel
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Ehxuast Fins, what are they good for?
So I keep seeing these little metal fins in my exhaust ports as I work on rebuilding my engine and I have to wonder, what the hell are they for?
I was talking to a second gen guy the other day and he told me to just take them out because it'll increase power or something. When I asked him how it would affect emissions, he just shrugged.
So here's the question, what are they for and what benefits do you get from removing them?
I was talking to a second gen guy the other day and he told me to just take them out because it'll increase power or something. When I asked him how it would affect emissions, he just shrugged.
So here's the question, what are they for and what benefits do you get from removing them?
#2
Smoke moar
If I recall Icemark said they're to reduce noise and the only benefit possible from removing them would be.... less restrictive exhaust outlet?
haha
Oh I think he said they're "exhaust inserts"
haha
Oh I think he said they're "exhaust inserts"
#4
Rotary Freak
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I read somewhere that it's also supposed to reduce the high pitch rotary noise.
From a training manual:
Here's how exhaust gases flow through them
From a training manual:
Multi-chamber port insert:
A partition has been provided within the insert to create a two stage opening action of the exhaust port for smoother exhaust flow.
A partition has been provided within the insert to create a two stage opening action of the exhaust port for smoother exhaust flow.
#7
Wrkn Toyota, Rootn Wankel
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So what exactly do they mean by smoother flow?
So far, we still don't understand what they are supposed to do exactly other than restrict exhaust in a "two stage" manner...
So far, we still don't understand what they are supposed to do exactly other than restrict exhaust in a "two stage" manner...
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#8
Old Fart Young at Heart
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First I've seen of those drawings or the 2 stage idea, sounds reasonable. Looks like I need to dl the Training Manual and read it, lol. They do quiet the exhaust conciderably. The turbos don't need them because the fins of the exhaust wheel break up the sound better than the insert ever could. Inserts do not need to be removed for porting, but it does help.
#14
The Shadetree Project
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Wow, seriously???? Those are commonly known as difusers and their only purpose is to quiet the exhaust. They were only used in 86-91 NA 13B's. Get rid of them for a louder faster car. Search the 2nd gen section for more info... They are cast as part of the insert, switch to turbo inserts or gslse ones. OR you can grind them out if you have 24 hours and a die grinder.
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they reduce noise about 3db, and power about 3hp.
considering what a bitch they are to take out, i'd just leave it
considering what a bitch they are to take out, i'd just leave it
#20
Wrkn Toyota, Rootn Wankel
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Wow, seriously???? Those are commonly known as difusers and their only purpose is to quiet the exhaust. They were only used in 86-91 NA 13B's. Get rid of them for a louder faster car. Search the 2nd gen section for more info... They are cast as part of the insert, switch to turbo inserts or gslse ones. OR you can grind them out if you have 24 hours and a die grinder.
Almost all the second gen guys keep saying that same line over an over again. But when I ask HOW they can't really answer it.
As for searching? under the terms, "Exhaust Diffuser" I found only 3/33 threads on the entire fourm that were worthwhile in reading, yet they had little technical information to explain how these things work exactly.
Sorry to sound ungrateful, but the diversity of and the amount of conflicting answers tends to make me want to know more about how it works.
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If all they do is quiet the exhaust how do they increase performance substantially?
Almost all the second gen guys keep saying that same line over an over again. But when I ask HOW they can't really answer it.
As for searching? under the terms, "Exhaust Diffuser" I found only 3/33 threads on the entire fourm that were worthwhile in reading, yet they had little technical information to explain how these things work exactly.
Sorry to sound ungrateful, but the diversity of and the amount of conflicting answers tends to make me want to know more about how it works.
Almost all the second gen guys keep saying that same line over an over again. But when I ask HOW they can't really answer it.
As for searching? under the terms, "Exhaust Diffuser" I found only 3/33 threads on the entire fourm that were worthwhile in reading, yet they had little technical information to explain how these things work exactly.
Sorry to sound ungrateful, but the diversity of and the amount of conflicting answers tends to make me want to know more about how it works.
http://www.wankel.net/~krwright/cars...%20Manual.html
section 1 and section 4....
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