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Old 02-10-2010, 03:37 PM   #1
kaotik78
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Join Date: Jul 2007
Location: Manchester, NH
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Default 07 2.5i UEL header swap power gain or loss?

I have a 07 2.5i wagon I am thinking about getting some UEL headers and a muffler and installing that on my car.

I have a sawzall, benchgrinder and a mig welder at my disposal so any modifications should not be much of a problem.

I have read thread after thread, wasting a bit of time, so I'll just ask.

Going from EL headers to UEL, what performance loss will be experienced? Significant, say 10hp, or is it something like 5hp or less?
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Old 02-10-2010, 04:01 PM   #2
GEE-OTTO
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Location: Arlington VA
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Quote:
Originally Posted by kaotik78 View Post
I have a 07 2.5i wagon I am thinking about getting some UEL headers and a muffler and installing that on my car.

I have a sawzall, benchgrinder and a mig welder at my disposal so any modifications should not be much of a problem.

I have read thread after thread, wasting a bit of time, so I'll just ask.

Going from EL headers to UEL, what performance loss will be experienced? Significant, say 10hp, or is it something like 5hp or less?

NO you wont lose any power or gain any over the 06 plus EL stock manifold design( it is actually a really good EL Manifold) . You will experience a shift in the power band to the right on a dyno plot.

IF you have moderate welding knowledge and exp you can simply mod a stock EJ255/7 manifold ( from a WRX, STi, OBXT, or LGT) by lopping off the Up pipe flange and welding a 2.5 O.D Three bolt flange at the correct angle to bolt up to your existing mid pipe. However I wouldn't MIG weld it! I would TIG weld it with a nickel rod or a 55ni rod ( i have a Lincoln Welder so i use their rods mostly) and preheat it to about 900 F before welding. I would use a beefy 3/8 Flange and keep in mind it doesnt have to mate to your stock pipe b/c you might get a custom one made or make it yourself.



OR


You can get a set of Borla Replica Headers and a Rallisport cat-pipe and extend your wires or have a track pipe made your call.

OR


You can wait till April that is when the Rallisport Racing 2.5i Bolt on UEL 2006+ Headers will be ready for sale
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Old 02-10-2010, 08:07 PM   #3
nairbmik
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Very very slight loss in power with the UEL, but if you pair it with an ideal exhaust (2.25-2.5") that'll let it breathe a bit easier it'll be fine
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Old 02-10-2010, 08:19 PM   #4
kaotik78
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Good points! Sadly the only access I have to a TIG would be my dad's ESAB, and that's in VA, along with my torch setup. Totally agreed to preheat for full pen.

Would this aftermarket header work, in the off chance I can't find a OEM wrx header?
Seeing that the pipe for the turbo is seperate, would make for cutting/modifying that flange a bit easier.

http://cgi.ebay.com/ebaymotors/02-07...Q5fAccessories

Last edited by kaotik78; 02-10-2010 at 08:22 PM. Reason: rephrased question
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Old 02-11-2010, 08:39 AM   #5
GEE-OTTO
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Quote:
Originally Posted by kaotik78 View Post
Good points! Sadly the only access I have to a TIG would be my dad's ESAB, and that's in VA, along with my torch setup. Totally agreed to preheat for full pen.

Would this aftermarket header work, in the off chance I can't find a OEM wrx header?
Seeing that the pipe for the turbo is seperate, would make for cutting/modifying that flange a bit easier.

http://cgi.ebay.com/ebaymotors/02-07-Impreza-WRX-Up-Pipe-Racing-Header-Combo-STI_W0QQcmdZViewItemQQhashZitem4a9e78b880QQitemZ32 0486291584QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAcce ssories

Yeah if you can't readily access a TIG and you have a MIG welder I would go the stainless steel route I think those are T304 and YES they are a hell of a lot easier to modify than cast stock headers. IF you look at the ebay header you can make an angled cut thru the collector and reposition the existing flange to clear the cross member then make the mid pipe end mate to the that.

I would chop the mid pipe end off ( about 5 inches back from the flange) and make that mate to the newly welded header collector section then simply cut a radius bend to the proper angle and weld that inline.

That UP will serve a good transition to the mid pipe if you cut it above that slight bend and angle it downward but not too much

Last edited by GEE-OTTO; 02-11-2010 at 09:12 AM.
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