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Old 04-16-2009, 07:54 PM   #1
Gr3en
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05 Corn Burner
Dirt Silver?

OMGHi2U Stock Header VS. Borla UEL

I am wondering which one flows better? I know the diameter of the borla is bigger, but since the stock is almost EL, would it flow better? it just kinda popped into my head on my way home from work today. It seems like I have lost some down low power on my RS, but I can't think of why?

I have Torque grind cams from Delta
Borla UEL headers
STi Mid-pipe
Devil Axle-back

Any thoughts?
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Old 04-16-2009, 08:06 PM   #2
07ImprezaMB
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I also have borla uel's on my 07 2.5i. They do indeed flow better than the stock el's. But all past arguments say that the aftermarket el's flow better than the aftermarket uel's........ but you dont get that sexy boxer rumble from the el's like you do with our borla's.
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Old 04-16-2009, 10:59 PM   #3
Ogden
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Quote:
Originally Posted by Gr3en View Post
I am wondering which one flows better? I know the diameter of the borla is bigger, but since the stock is almost EL, would it flow better? it just kinda popped into my head on my way home from work today. It seems like I have lost some down low power on my RS, but I can't think of why?

I have Torque grind cams from Delta
Borla UEL headers
STi Mid-pipe
Devil Axle-back

Any thoughts?
What's the overall diameter of the piping in the exhaust?

It seems like when the piping gets too big for the 2.5i, it costs you on the low end. I think that most folks say 2.25" to 2.5" is about the size you want. Anything bigger and it starts to cost you in the low end.
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Old 04-17-2009, 03:34 AM   #4
07ImprezaMB
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MY borla header and catpipe are 2.25 and i think my catback is some weird number like 2.36??? lol i dont know but its made for the 2.5i/2.5rs.
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Old 04-17-2009, 03:37 AM   #5
EdHilario
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Maybe the OP can benefit from some open source tuning.
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Old 04-17-2009, 10:32 AM   #6
Dammod
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Do you all have a 2 small pipes coming from the engine on either side (4 all in all) then further on it joins to two and then 1? I got custom headers made but in only gets to 2.5" when in gets to the main zorst. the 4 to 2 and the 2 to 1 pipes are alot thinner then the main zorst. Is this right?

Sorry for the hi jack.
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Old 04-17-2009, 10:36 AM   #7
Gr3en
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So.. Which do you think will flow better? The UEL is a lot longer and is a bigger diameter, but the stock is more direct to the cat?
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