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Exhaust System

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flat_iv Seriously Crusin Dubber

107 posts · joined May 2005 ·

#430365
Thinking of building my exhaust system with dual mufflers and retaining the exhaust ports out of the factory location. The only thing that I am afraid of is loosing the boxster sound on the Subaru engine. I have searched the NASICO forum and equal length headers seem to cancel out the boxster sound. Any advise on this system or a better way is appreciated.

Thanks

[ Edited on 19/11/2005 by flat_iv ]

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pete wood 23 Windows of Awesome

6,828 posts · joined Jan 2004 ·

#430383
just a thought, but by merging the header near the flange as you have, they won't strictly equal length anyway. And personally, I'd be worrying more about flow characteristics than sound.
"stoopid is stronger than axles"
http://drivingnotpolishing.blogspot.com.au/

flat_iv Seriously Crusin Dubber

107 posts · joined May 2005 ·

#430385
Most all American Hot rods have an X-pipe in the system and tend to increase HP. But the X- pipe isnt normally this close to the header. Originally I was thinking of 2 1/4" pipe but I might think about 2 1/2". But I believe that 2 1/2" pipe will loose some torque. I might send this pic to the guys at Magnaflow and see if they can give some input

[ Edited on 19/11/2005 by flat_iv ]

pete wood 23 Windows of Awesome

6,828 posts · joined Jan 2004 ·

#430390
i'm no expert, but i know there is a relationship between the size of the pipe and gas velocity. I know for turbo engines the idea is to keep the header size on the smallish side to keep the gas velocity up. Not sure how that works in atmo motors, but i would have thought you'd be trying to keep a setup where the length of the pipes creates a harmonic that actually extracts the gases, hence the name 'extractors' used for some headers. Wouldn't the X pipe screw with this effect if it is too close to the heads?

Def a good idea to get some exhausts specialists to look at it. Let us know what you find out, coz i'd like to change my exhaust at some stage.
"stoopid is stronger than axles"
http://drivingnotpolishing.blogspot.com.au/

ratbug aka toddy101

439 posts · joined Jan 2003 ·

#430420
I deliberately made my exhaust unequal to get the boxer sound, and it worked!
I have a 2" pipe coming out of the right hand side cylinders, going across the front of the engine where it then meets up with the 2" pipe from the left hand side cylinders.
It then does a 180degree turn and goes through the cat. converter and muffler and finishes on the right hand side.
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flat_iv Seriously Crusin Dubber

107 posts · joined May 2005 ·

#430500
ratbug, do you have any pics to see?

RENNWAGEN Seriously Crusin Dubber

158 posts · joined Sep 2003 ·

#430563
Increasing exhaust back presure does not help torque. Read a book called 21st century performance there are some test results in there that outline this. With a turbo smaller headers to keep up exhaust velocity will help in spool up then go as large as you can on the dump side.