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Discussion Starter #1 (Edited)
so I am getting ready to fabricate/install a dual exhaust set up on my car.
I already have 3" DP,3" mid pipe,etc. All the way into a 3" HKS Carbon Ti muffler. Tomorrow i will be ordering another 3" HKS Carbon Ti muffler along with everything else I will need for the install.

first question, for Maximum flow should I use this piece:



Or this piece made by MagnaFlow :



& I have even seen this done:



I am doing this because i like the way it looks but i am also looking forward to benefit from the dual 3" exhaust. Will i actually be benefiting from this or will i be compensating some power/spool,etc for Looks?
here is some info on my set up :

PT67 DBB Turbo, Tubular manifold, Tial 44m wastegate.
Head- HKS 264 intake cam, 272 exhaust cam. BC springs/retainers. ARP studs
Block- CP forged pistons, Eagle H beam forged rods, Clevitte racing bearings, ARP bolts, ARP studs

i read on SF that a dual 3" will outflow a single 4". but will this set up be louder then a single 4"?
I have no resonators,no cats,etc.

Thanks in advance for your input.

-Juan.

**** UPDATE 2/18/08 ****
Dual exhaust project is finally complete. This was definitely alot more work then i expected. but i am happy with the results.

Piping and HKS carbon ti came in....




Custom hi-flow Y pipe...




At the bodyshop getting new rear bumper painted/installed....



Goodbye' custom rear bumper...



Hello' JDM altezza rear bumper/JDM TRD Neo rear valance modified for dual exhaust...



Leaving the bodyshop, and heading back to the Performance shop....



Test fitting...




Time for finishing touches After lots of hours of labor, calculating, modifying,routing,etc...




And waa' Laa'... finally done, and back on the road...
right now both mufflers are not perfectly angled the same because the passenger side muffler hanger broke.so it was modified for the time being. i did order a new one, and once it comes in..i will make the adjustments.





- Juan
 

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so I am getting ready to fabricate/install a dual exhaust set up on my car.
I already have 3" DP,3" mid pipe,etc. All the way into a 3" HKS Carbon Ti muffler. Tomorrow i will be ordering another 3" HKS Carbon Ti muffler along with everything else I will need for the install.

first question, for Maximum flow should I use this piece:



thats what i have on mine..
 

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well the thing is your not really going to benfit power wise. Reason obviously because it isnt true dual. You still can only flow so much through the first piece of 3" pipe.
 

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^^^

That said, a full 3" exhaust has been sufficient for even the highest powered IS's so you shouldn't have an issue. Your car should be quieter with two mufflers though as discussed somewhere else in Go Faster.
 

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Discussion Starter #5
^ sounds good. A quiter exhaust will be sweet.

I already ordered another HKS carbon ti muffler last night.

Still haven't decided on what Y pipe to use.
 

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The magnaflow was discussed elsewhere too and the verdict was it wouldn't be good for smooth flow. Either the first one (by the way who makes that) or a custom one like Sophiesleeps did. Cut two pieces at 45 degrees or so and wel them together, which should split the flow very well and doesn't shouldn't have much if any turbulance.
 

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have a custom Y-made to maximize the flow. Those two peices above (especially the magnaflow) is a poor design in my opinion for a split.

I have a dual exhaust, the car didnt become much quieter. It could be the mufflers, or the car could need a decent mid muffler.

If you are hoping to do this because of noise and still maintain power, its only going to change the tone up. Throw on a long muffler underneath the car with a resonator afterward.
 

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Discussion Starter #8
The magnaflow was discussed elsewhere too and the verdict was it wouldn't be good for smooth flow. Either the first one (by the way who makes that) or a custom one like Sophiesleeps did. Cut two pieces at 45 degrees or so and wel them together, which should split the flow very well and doesn't shouldn't have much if any turbulance.
it is made by "Norell Muffler & exhaust"
here it is...
eBay Motors: Exhaust 3'' Y pipe dual custom kit clamps clamp (item 300192738979 end time Jan-28-08 14:36:09 PST)

and yeah i decided to go with a custom Y pipe for better/smoother flow like
sophiesleep's custom one. hopefully he can make one for me..or i will have a shop here make one....
here are some pics as he also compares it to the magnaflow:






 

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have a custom Y-made to maximize the flow. Those two peices above (especially the magnaflow) is a poor design in my opinion for a split.

I have a dual exhaust, the car didnt become much quieter. It could be the mufflers, or the car could need a decent mid muffler.

If you are hoping to do this because of noise and still maintain power, its only going to change the tone up. Throw on a long muffler underneath the car with a resonator afterward.
i have a custom ypipe made for mine, and im running without a cat or res, and it is no where near quiet. but it has a very unique sound to it. even better if youre boosted.
 

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If you guys want a quieter exhaust, you can build a cross over pipe just before the pipe enters the two mufflers... By tying them together very late in the exhaust stream, it smoothens out the exhaust pulses and gives you a smoother less raspier note.
 

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Discussion Starter #11
Dual exhaust was completed last night.

I updated the first/original post with pictures.

-Juan M.
 

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Discussion Starter #13
sound clip!!!
haha, car was dropped off at PFS today. so unfortunately i wont be able
to record a sound clip for like another 2 weeks.
 

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Well it looks like a good job (ideally all those angles should be mendrel but no biggie) and I like the mufflers and the bumper, good sh*t.
 

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Very nice work. I think that one of the main reasons for dual exhaust like this is mostly for cosmetic and possibly sound. Maybe its just me, but I love dual exhaust, simply because I like everything symmetrical haha.

Again, nice work, hopefully someday I will have dual exhausts...
 

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juan, looks good, but it isnt really a "dual" exhaust. its an in line 6, they will never be a true dual exhaust.

but arguements aside, it looks liek they did a good job.
 

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Discussion Starter #17
Thanks mike.

& ofcourse it isnt a "true dual exhaust".. a true dual exhaust is actually illegal in the state of NJ. The shop definitely did a awesome job. no hack job here.. alot of people have actually hurt their exhaust flow while trying to do this to their IS.. but the shop made sure they routed everything correctly and made me a custom Y pipe to optimize the flow.
 

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Thanks mike.

& ofcourse it isnt a "true dual exhaust".. a true dual exhaust is actually illegal in the state of NJ. The shop definitely did a awesome job. no hack job here.. alot of people have actually hurt their exhaust flow while trying to do this to their IS.. but the shop made sure they routed everything correctly and made me a custom Y pipe to optimize the flow.
juan, i asked my cousin(NJ state police) - he has no idea abotu this law for dual exhaust. who told you this?
 
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