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Old 02-27-2013, 11:44 AM
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Default 3" Exhaust

Riddle me this. Is one 3" exhaust the same thing as having two 1 1/2" duals? Simple math tells me that it is. I would think that for the kind of power these LS engines are making, that you would need @ the min two 2 1/2 pipes, or a some kind of 5" oval? So I would like all of the so called exhaust guru's to chime in and set me straight.
Old 02-27-2013, 11:52 AM
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Let me throw this in

http://www.exhaustvideos.com/faq/how...pipe-diameter/
Old 02-27-2013, 11:58 AM
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This one says that a 3 1/2" pipe is the same as two 2 1/2" pipes? I dont get it?




http://www.angelfire.com/my/fan/Exhaust_Pipe_Size.htm
Old 02-27-2013, 12:27 PM
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https://ls1tech.com/forums/2987587-post19.html
Old 02-27-2013, 12:42 PM
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OMG, jrp from 2005! is this guy still alive?....
Old 02-27-2013, 01:24 PM
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I've often wondered the same thing... He was quite active "back in the day."
Old 02-27-2013, 01:54 PM
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Assuming your exhaust pipe is round, you need to figure out the area of the tubing to you want to use, not the radius or diameter. A 3" pipe will flow far more than two 1.5" pipes.

You also have to take into consideration the thickness of the tubing used. Exhaust pipe is measured by the outside diameter. A 18 gauge 3" pipe will flow much more than a schedule 80 3" pipe.
Old 02-27-2013, 02:38 PM
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Originally Posted by MX6.0
Assuming your exhaust pipe is round, you need to figure out the area of the tubing to you want to use, not the radius or diameter. A 3" pipe will flow far more than two 1.5" pipes.
this. there is an exponential factor to consider when comparing area. it seems that a well bent 3" setup works well up to ~400whp.
Old 02-27-2013, 02:49 PM
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Or just run 3" duals and **** the math
Old 02-27-2013, 03:19 PM
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Just to put that in perspective for you the primaries on your headers are larger then 1.5", and that would be half (or in my case less than half) of the diameter of your collectors.
Old 03-01-2013, 10:09 AM
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Originally Posted by slow ride 02
So I would like all of the so called exhaust guru's to chime in and set me straight.
You don't need an exhaust guru. You need a high school degree.
Old 03-01-2013, 02:21 PM
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Originally Posted by Marc 85Z28
You don't need an exhaust guru. You need a high school degree.
Thanks for the input Marc. You my friend, are a class act....
Old 03-02-2013, 04:51 AM
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Two 2" dia pipes are NOT equal or even all that close to one 4" pipe. You can almost fit those two 2" pipes inside of that 4" pipe. What about all that unaccounted for space in the 4". Hence the area of a circle below.

Area of a circle. PI*r^2=A

2" dual = 6.2in^2
2.5" dual = 9.8in^2
3" dual = 14.2in^2
3" single = 7.1in^2
3.5" single = 9.6in^2
4" single = 12.6in^2

Dual 3" exhaust is good for about 800bhp. Single 3" about 370bhp. I have found that dual 3" into a single 3.5" makes for a good balance of noise and power. It is limited to about 500bhp though before it starts pulling power from a theoretical maximum.
Old 03-08-2013, 02:24 PM
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Originally Posted by Marc 85Z28
You don't need an exhaust guru. You need a high school degree.
not even that. they teach this **** in like 8th or 9th grade.



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