just wondering what affects would it have running two smaller exhaust setups (i.e. two 2.25 or 2.5 exhausts) compared to a single large exhaust system...

i'm only asking because im wondering if this would at all affect the exhaust note and loudness.

i still think my 3 inch exhaust with two resonators is still too loud

 

what length resonator do you have?

 

My friend built a twin 2 inch from turbo back on a 88 Mazda 323 turbo with magnaflow and it was noticeably quiter than his 3 inch back. As for flow...on paper they are about the same, but not sure about real life.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Boostage &raquo;</TD></TR><TR><TD CLASS="quote">what length resonator do you have?</TD></TR></TABLE>

moroso spiral flow and magnaflow race muffler

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ELSpool &raquo;</TD></TR><TR><TD CLASS="quote">My friend built a twin 2 inch from turbo back on a 88 Mazda 323 turbo with magnaflow and it was noticeably quiter than his 3 inch back. As for flow...on paper they are about the same, but not sure about real life.</TD></TR></TABLE>

((2 * pi)^2) * 2 = 78.9568352

(3 * pi)^2 = 88.8264396


based on circular area alone, the 3 inch setup would have a larger area for exhaust gases to pass through

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by igo4bmx &raquo;</TD></TR><TR><TD CLASS="quote">

((2 * pi)^2) * 2 = 78.9568352

(3 * pi)^2 = 88.8264396


based on circular area alone, the 3 inch setup would have a larger area for exhaust gases to pass through</TD></TR></TABLE>

false. pi r^2, only the r buddy, not the pi. the 2*2^2*pi is more... 2*pi*r^2

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by LSTEG96 &raquo;</TD></TR><TR><TD CLASS="quote">false. pi r^2, only the r buddy, not the pi. the 2*2^2*pi is more... 2*pi*r^2 </TD></TR></TABLE>
whoops
you are right
(pi * (2^2)) * 2 = 25.1327412
pi * (3^2) = 28.2743339

still the 3 inch catback yield more exhaust flow area
however, two dual 2.25 inch piping
(pi * (2.25^2)) * 2 = 31.8086256

would be better?

 

If you really want to work on the physics of it....it's not just the area here. A lot of other things come into effect. Things flow better in a single chamber design rather then multi chamber desgins because of flow restrictions and turbulence even for the same flow area.

So technically it's better to have one large exhaust rather then 2 smaller ones of the same flow volume. In real life though I really thing this won't matter. You're talking about a very very very small restriction on a motor producing 2xx horsepower...you may notice 1hp difference. As far as the exhaust note goes I'm sure the tone changes, but i have no experience

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by adseguy &raquo;</TD></TR><TR><TD CLASS="quote">If you really want to work on the physics of it....it's not just the area here. A lot of other things come into effect. Things flow better in a single chamber design rather then multi chamber desgins because of flow restrictions and turbulence even for the same flow area.

So technically it's better to have one large exhaust rather then 2 smaller ones of the same flow volume. In real life though I really thing this won't matter. You're talking about a very very very small restriction on a motor producing 2xx horsepower...you may notice 1hp difference. As far as the exhaust note goes I'm sure the tone changes, but i have no experience</TD></TR></TABLE>

yeah i can see a problem when you divert a stream of gas into two seperate chambers. It would be interesting to see if the ricer setup would actually work well in quieting down, yet keeping gases flowing for our boosted cars

 

Maybe it's just your muffler. I run a Thermal 3", no resonator, no cat, no silencer cone, and it's very quiet.

 

whats a muffler?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rmcdaniels &raquo;</TD></TR><TR><TD CLASS="quote">Maybe it's just your muffler. I run a Thermal 3", no resonator, no cat, no silencer cone, and it's very quiet.</TD></TR></TABLE>

are you sure??!!

one a scale of 1-10 1= stock exhaust 10= open downpipe.

what is it?

 

I'd rate it around a three or four. My wife agrees, and she's alot more sensitive to it than I am. I had a Tanabe, which was a loud obnoxious POS, then I got a custom made 2.5" with two Magnaflow 4" SS cans and a Carsound 2.5" cat, which was much better than the Tanabe. The Thermal is even quieter, it has a nice low sound that sounds good. Of course if I wind it up to 9000 RPM it will get pretty loud, but I no longer wake up everybody in my neighborhood if I come home late. It also came with a removable silencer cone that can be put in the muffler to make it almost stock quiet, but I've never had to use it.

EDIT - I can also talk on my cell phone when I am driving on the highway with no problems. With my last exhaust it was difficult to do, with the Tanabe I'd never hear it ring.

 

I dont know about on a honda, but my friend has a DSM 2.0l (4g63)2.5dp 3in exhaust, no cat apexi n1 muffler, and on that scale you just mentioned I'd say its about a 5 (which isnt very loud, IMO) and has a very nice note (deep and smooth, T28 turbo) to it and gets quiter with spool.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rmcdaniels &raquo;</TD></TR><TR><TD CLASS="quote">I'd rate it around a three or four. My wife agrees, and she's alot more sensitive to it than I am. I had a Tanabe, which was a loud obnoxious POS, then I got a custom made 2.5" with two Magnaflow 4" SS cans and a Carsound 2.5" cat, which was much better than the Tanabe. The Thermal is even quieter, it has a nice low sound that sounds good. Of course if I wind it up to 9000 RPM it will get pretty loud, but I no longer wake up everybody in my neighborhood if I come home late. It also came with a removable silencer cone that can be put in the muffler to make it almost stock quiet, but I've never had to use it.

EDIT - I can also talk on my cell phone when I am driving on the highway with no problems. With my last exhaust it was difficult to do, with the Tanabe I'd never hear it ring.</TD></TR></TABLE>

how is it going from a stop?
for me the highway cruising isn't bad, but when you are in stop and go traffic it stinks...
mine is like a 6-7 on that scale, and can talk while cruising on highway but thats about it...
thats with 1 -12 inch moroso spiral flow and 1 - 18 inch dynomax race muffler and 1- magnaflow muffler

did you buy the thermal kit or justthe muffler?

 

Not too bad from a stop, I do have to wind it up a bit from a stop though, but that's just because I have a 6-puck unsprung hub clutch with an 8 lb flywheel. It's definitely louder than stock, but everyone that has heard it says that it doesn't sound obnoxious anymore. I was out the other night at 2 A.M. working on the car, revving it up in the driveway to test my belt tensioner and I really pissed off my neighbors across the street, but the tailpipe was aimed right at their house. Nobody else complained and it didn't wake up my kids, which my old exhaust used to do. Also remember that that's with the silencer cone removed. The guy at Thermal that I talked to said that it is much quieter with the cone in.

I bought the kit from Endyn, I don't know if they sell the muffler separately.

Here's some pics of my old custom exhaust:





Here's the Thermal:




Those pics are kind of crappy, but the Thermal exhaust is a thing of beauty, it fits perfectly and the quality is great. Here's a better pic from the Thermal site:



If you do get the Thermal, make sure you specify that you want a removable silencer cone. When I ordered mine, most dealers, including Endyn, didn't know it was an option.

 

https://honda-tech.com/zero...96997

sound/video clip of dual exhaust... i think it sounds better than single to me for thinking that