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Discussion Starter #1
so heres what im thinking, taking my test pipe 2.5, and installing a reducer 2.5 to 2 inside the testpipe, as a silencer. it should work in theory but havent tried it yet. what do you think.

the exhaust is 2.5 straight to muffler dual tip. so i cant put a silencer at the end.

its to loud for my taste and was wondering if this would work.

even though this set up is not going into a supra i still need your advice.

basically, i need to know if this would work.
 

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ummm...

i'm pretty sure that won't do a whole lot. I'd have some web-pages for ya, but i'm away from my normal computer right now. i can get you those exhaust links sunday night. Ask shawndude, he's really good at exhaust stuff.
 
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Hmm, funny way to go about it. :)

Any restriction automatically works as a silencer. So I'd say your restriction will work well, but flow very poorly.

Can't you just use the real catalytic converter instead? It would probably silence just as well, and help emissions also.

What noises are you trying to silence? The deep rumbly ones, or just everything in general?

Was the stock resonator removed? If so, you could fit it back on, without reducing flow very much while silencing the annoying frequencies greatly.

What car is it by the way?
 

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Discussion Starter #8
i see, its a 240sx s13

the stock exhaust uses a box resonator and a muffler with 2" piping. i replaced with a 2.5 piping a magnaflow muffler. exellant flow, straight thrugh, however its anoying as hell past 3k, its louder than my supra, LOL

its a low tone noise like a turbo exhaust, but louder, non rice at all.
just too loud for my taste.
i agree restriction = less noise. however at this point i have tried the stock cat which muffled it a bit but not enough, but it did give me a nice TQ.

but common sence tells me if im gonna get the same flow as a stock system with my NEW CREATION added on, why not put the stock system back in. instead of wasting more money, BUT if i can get a little beter flow plus the NEW Silencer set up inthe test pipe ill be happy, with less noise offcouse.

no one has really answered the question right till now, Thanks

not even in 240sx forums.
 

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Discussion Starter #10
will the stock resonator be too restrictive?

im not too familiar with resonators.
 

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a hemholz style resonator is a really good resonator... resembles a glass-pack, but flows a lot better. I'm pretty sure they're cotsly though
 

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lol, well thats good. :D :D

how much of a noise reduction was there?
 
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anyone bother to look at sound rooms and notice how they keep
echo's from occuring?

an exhaust pipe, enclosed, is basically just a long tube that sound waves
bounce off of on the inside; if you add restrictions, you won't
be doing yourself much good.

however, theoretically, if you were to add alternating ridges
that rise from the outer curve to the center inside of the pipe by
about .25" then you would effectively reduce the echo and cancel
out alot of the noise; no?

sound travels so fast that you don't notice there's an echo in
an exhaust pipe, but there is. at least I think in theory, if you
were to provide a surface on the interrior of the pipe which
would not reflect sound waves very well, then you could reduce
the noise.


just a thought?
 

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Discussion Starter #17
skuzzah said:
anyone bother to look at sound rooms and notice how they keep
echo's from occuring?

an exhaust pipe, enclosed, is basically just a long tube that sound waves
bounce off of on the inside; if you add restrictions, you won't
be doing yourself much good.

however, theoretically, if you were to add alternating ridges
that rise from the outer curve to the center inside of the pipe by
about .25" then you would effectively reduce the echo and cancel
out alot of the noise; no?

sound travels so fast that you don't notice there's an echo in
an exhaust pipe, but there is. at least I think in theory, if you
were to provide a surface on the interrior of the pipe which
would not reflect sound waves very well, then you could reduce
the noise.


just a thought?
i think resonators are built like that. but i dont think from the response in the other forums, it made any significant changes in loudness, but rather just tone
 
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Not sure if echo theory is the best for this.

Why exhaust noise is loud, is due to rapid and violent expansion of the gasses. A reason why guns, explosions, and firecrackers are also loud.

The idea is to destroy these strong pressure waves, so instead of one big wave, we have bunch of smaller, quieter ones. It is equivalent to destroying a wave in the ocean, by putting up dams and obstructions, as this creates bunch of smaller waves.

A resonator takes a big wave fluctuating (resonating) at one frequency, and using proper sizing generates it's own resonance at the same frequency but opposite phase. Two waves of the same magnitude (size) will cancel each other if they hit each other at exactly the opposite phase. Hence why resonators work only on a relatively narrow frequency range of the noise, and must be tuned properly or they won't work.

Take two subwoofers, wire one opposite of the other (flip the + and - wires going to one), and play some music through them. They will cancel most of each other out and you won't be able to hear much. Same idea.
 
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old thread but i couldnt believe what i read

You are just asking for back pressure. The last thing you want to do is rapidly and repeatedly change the direction of air-flow in your exhaust and create turbulence.

This is not how the design of sound studios work 'in theory'. Their custom design is more than just ridges protruding from the walls, and they are not a representation of how air and sound flows thru a pipe.

Sounds like pornadict guy found something that works well enough for him. Unfortunately, more flow does equal more sound but mostly because you want a bigger exhaust to handle that flow. What some people dont realize is that there is a lot of sound coming from your intake pipes too. Try a pre-muffler setup.




skuzzah said:
anyone bother to look at sound rooms and notice how they keep
echo's from occuring?

an exhaust pipe, enclosed, is basically just a long tube that sound waves
bounce off of on the inside; if you add restrictions, you won't
be doing yourself much good.

however, theoretically, if you were to add alternating ridges
that rise from the outer curve to the center inside of the pipe by
about .25" then you would effectively reduce the echo and cancel
out alot of the noise; no?

sound travels so fast that you don't notice there's an echo in
an exhaust pipe, but there is. at least I think in theory, if you
were to provide a surface on the interrior of the pipe which
would not reflect sound waves very well, then you could reduce
the noise.


just a thought?
 

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damn noobs been grave diggin' again....go figure.
 
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