Custom True Duals on s4
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Banned. I got OWNED!!!
Joined: Dec 2003
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From: here.
Custom True Duals on s4
i think i want to attempt getting custom true duals made for my n/a.
im thinking the non-collecting RB header, twin pipes to twin presilencers, then piped straight to the mufflers.
the header would cost $170, and each presilencer would be $200 a piece....i already have a cat back system id cut and use the mufflers from that. All custom piping would be either 2" or 2 1/2"
now the question, with it being a s4, am i gonna lose all of my backpressure? what can i do?
im thinking the non-collecting RB header, twin pipes to twin presilencers, then piped straight to the mufflers.
the header would cost $170, and each presilencer would be $200 a piece....i already have a cat back system id cut and use the mufflers from that. All custom piping would be either 2" or 2 1/2"
now the question, with it being a s4, am i gonna lose all of my backpressure? what can i do?
**-P I drive a miata.
Joined: Jul 2002
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From: albany, GA
can you weld?
do not make the piping any wider than it needs to be. I would think that, as the exhaust travels down the pipe it cools, and thus contracts. This would mean that you would need less piping further down the pipe than you would at the beginning. I would think that ideally the exhaust would be able to keep the same speed throughout the pipe. This would require having the pipe progressively shring the further you went down the pipe.
do not make the piping any wider than it needs to be. I would think that, as the exhaust travels down the pipe it cools, and thus contracts. This would mean that you would need less piping further down the pipe than you would at the beginning. I would think that ideally the exhaust would be able to keep the same speed throughout the pipe. This would require having the pipe progressively shring the further you went down the pipe.
Senior Member
Joined: Jan 2003
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From: MA
I have custom true duals from header back done by pervious owner. I have no clue if I even have a damn O2 sensor hooked up ( gotta check that when I put it on the road). I doubt my 5th and 6th port opens, I should find out in 3 weeks though. I have a pic of it, but not a good pic of it though. Hope this help.
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Joined: Jan 2004
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From: The Abyss-also cincinnati,ohio
Cross sectional area of a single pipe 3" exhaust is 7.06"^2, 3.5" is 9.61"^2, and 4" is 12.57
Dual 2" is 6.28, and dual 2 1/2" is 9.80.
Needless to say there will be other figures to take into account such as additional restrictions for two pipes, however its probably a good idea for 1, to run an x or H pipe to equalize backpressure at the very least. However the difference in cross sectional area is not negligible and must me taken into account, especially if you do not plan to run cats. Just ask yourself, would you want a 3.5"single pipe exhaust system?
Dual 2" is 6.28, and dual 2 1/2" is 9.80.
Needless to say there will be other figures to take into account such as additional restrictions for two pipes, however its probably a good idea for 1, to run an x or H pipe to equalize backpressure at the very least. However the difference in cross sectional area is not negligible and must me taken into account, especially if you do not plan to run cats. Just ask yourself, would you want a 3.5"single pipe exhaust system?
If your going to do this don't use FC presilencers use the ones that mazdatrix used which are for the FB I think. Use 2" tubing or 2.5 at the most. You will have to figure out how to make your ports work unless you can get a fitting made for the setup to hook onto the ports.
If your going to do an X pipe or H pipe I wouldn't even bother with making the true duals because an H or X pipe just makes it a normal exhaust so your better off buying a collected setup.
If your going to do an X pipe or H pipe I wouldn't even bother with making the true duals because an H or X pipe just makes it a normal exhaust so your better off buying a collected setup.
