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Old 06-19-2013, 06:05 PM   #1
dangerousatom
Scooby Specialist
 
Member#: 70710
Join Date: Sep 2004
Chapter/Region: Tri-State
Location: Quakertown/AREA1320 391whp
Vehicle:
2002 04STi Swaped RS
w/PPGS & 02 Wagon w/PPGs

Default When to go headers vs PnP OEM & X-pipe

I have not written a question post like this in years!!

I have been working on Subys since 04, and I cant believe there is not a thread that I can find witch gives some info on when its no longer worth using the stock PnP exhaust collectors and a after market X-pipe.

I fully agree with keeping the stock bits with a VF series turbo and even a 16g, but I feel aftermarket headers will out weigh the gains from PnP the stock parts on a larger ( then 16g ) turbo. I know the OEM parts may spool faster but there is obviously an efficiency/choke point at where the exhaust needs more room to flow vs creating more pressure for quicker spool.

Im currently running:
Blouch 18g-xt-r on a 2.0L EJ205
ProcessWest TMIC
TGV Deletes
STi pinks
PnP manifold and x-pipe
UP-EWG
3" DP
catless 3" lightspeed titanium back.

This is only temporary as I have been working on a EJ207 long block and its about time to drop it in with 1000cc injectors and functioning AVCS. Its looking like 23-25psi is my target boost, since 21psi was where I was on the above setup with a 16g until that turbo gave up its oil seals. So in short Im looking for factual info on weather its more beneficial to use UL tube headers for the 18g or to stay with the OEM PnP bits.
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Old 06-19-2013, 09:39 PM   #2
jaxscuby
Sammo Hung
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Member#: 10613
Join Date: Sep 2001
Chapter/Region: South East
Location: S Ga / Hell Rock
Vehicle:
2002 USDM WRX
WRB

Default

i suggest you take a ride in ul / el / pnp stockers.

everyone will throw in their 2 cents. but for unbiased information
a ride will let you make up your own mind.
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Old 06-19-2013, 11:34 PM   #3
dangerousatom
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Member#: 70710
Join Date: Sep 2004
Chapter/Region: Tri-State
Location: Quakertown/AREA1320 391whp
Vehicle:
2002 04STi Swaped RS
w/PPGS & 02 Wagon w/PPGs

Default

Mmm ya that's kind of what I was figuring . . It's a personal preference on spool to RPM to squeasing out all the power possible. Ill more then likely stay with the PnP manifold until I get a good deal on a UL headed.
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Old 06-20-2013, 01:59 AM   #4
mod maniac
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Join Date: Nov 2011
Chapter/Region: SCIC
Location: mariposa ca.
Vehicle:
2&4 fxt & fxt sti
Fullers Garage

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The stock manifold is an awful design. An unequal header is a better design if you like that sound (yuk). An equal length is the best design. You will gain some by improving. Is it worth it, that's for you to decide. I try to gain every hp I can get.
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Old 06-20-2013, 09:02 AM   #5
rexblake
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Location: FoCo
Vehicle:
2010 Audi S4
Black

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There is really no reason to go with an aftermarket ul header when a el header will do everything better. If your going to go aftermarket, do yourself a favor and buy a elh. As for when it's necessary, I'd certainly think the better spool characteristics if a quality elh would be beneficial almost at any point. Power probably won't be affected until it's a larger turbo. I swapped to my Perrin elh when I went with a Dom 3xtr. Pnp with cross pipe before that for my td04, 16g, and 68hta.
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