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Old 09-30-2021, 12:13 PM   #1
BlackFighter
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Member#: 193940
Join Date: Nov 2008
Location: Philly
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2004 WRX STI Black
RalliSpec Shortblock

Default What exhaust for the track?

I'm currently trying to put together a fun dedicated track car and need some opinions on exhaust. The car came with a Tanabe JDM DP and exhaust. We switching to rotated setup so the DP had to be replaced with a rotated DP.

Since the DP was JDM, the JDM exhaust will not mate properly to the rotated US DP. My option is to modify the exhaust to fit the US length DP or replace the exhaust to a US exhaust.

What are you guys running on the track?

At first I will be doing track days without any classes, but later might want to start SCCA classes where the ruling is no more then 103dB, if I'm not mistaking.
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Old 09-30-2021, 01:48 PM   #2
subydude
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Sparkly

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Just about any 3" exhaust will be fine. The ones with a suitcase muffler (like the maddad whisper) will help with sound, but even the grapefruit shooters will generally be ok if you repack them. I have an older Ti magnaflow and put a burns muffler in between while also packing both with new muffler material. It blows about 96 at full song and sounds reasonable.

Does your JDM DP have the flange for a TS turbo or is it the standard turbo and just different length? It's not hard to cut and weld stuff, but if it's the JDM TS flange those are kind of hard to come by so it might be worth it to sell and buy something else.

Regarding sound, if you're doing EWG you'll want to plumb it back in or put a muffler on it as that's usually the part that exceeds sound.
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Old 09-30-2021, 02:37 PM   #3
BlackFighter
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Already have it up for sale, its TS.

https://forums.nasioc.com/forums/sho....php?t=2936906

Ya the EWG might be a problem.
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Old 10-01-2021, 03:37 PM   #4
Thorium06
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Default

Quote:
Originally Posted by BlackFighter View Post
Already have it up for sale, its TS.

https://forums.nasioc.com/forums/sho....php?t=2936906

Ya the EWG might be a problem.
You'll want to route that back into the downpipe for several reasons. It is loud AF, might get you into sound trouble, several rulesets have regulations about where an exhaust can exit, they tend to melt **** like power steering lines, axle boots ect, and then you're going to have a bad time. Routing to the downpipe helps all of the above and then you don't have to think about it anymore.
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Old 10-01-2021, 04:15 PM   #5
Jefe159
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11 STI
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regarding noise level, I'd just get something as conservative as you'd be happy with on the street. SCCA has dB limits but whether they care or not is a different story. Certain tracks also have dB limits and they tend to care more so you may do some homework to see what your "local" track requirements are.
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Old 10-02-2021, 05:59 PM   #6
BlackFighter
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Ya, really did not want to butcher up my brand new Tigwerks rotated downpipe. Got some thinking to do. Thanks guys.
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