Welcome to the North American Subaru Impreza Owners Club Thursday March 28, 2024
Home Forums Images WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Go Back   NASIOC > NASIOC Technical > Normally Aspirated Powertrain

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.







* As an Amazon Associate I earn from qualifying purchases. 
* Registered users of the site do not see these ads. 
Reply
 
Thread Tools Display Modes
Old 02-10-2010, 03:37 PM   #1
kaotik78
Scooby Newbie
 
Member#: 153984
Join Date: Jul 2007
Location: Manchester, NH
Vehicle:
2007 Impreza
Silver

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?
* Registered users of the site do not see these ads.
kaotik78 is offline   Reply With Quote
Sponsored Links
* Registered users of the site do not see these ads.
Old 02-10-2010, 04:01 PM   #2
GEE-OTTO
Scooby Specialist
 
Member#: 201277
Join Date: Jan 2009
Chapter/Region: MAIC
Location: Northern VA
Vehicle:
2008 08 QSM 5MT LGT
QSM

Default

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
GEE-OTTO is offline   Reply With Quote
Old 02-10-2010, 08:07 PM   #3
nairbmik
Scooby Specialist
 
Member#: 220259
Join Date: Aug 2009
Chapter/Region: MAIC
Location: HoCo & College Park
Vehicle:
09 2.5i
SSM

Default

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
nairbmik is offline   Reply With Quote
Old 02-10-2010, 08:19 PM   #4
kaotik78
Scooby Newbie
 
Member#: 153984
Join Date: Jul 2007
Location: Manchester, NH
Vehicle:
2007 Impreza
Silver

Default

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
kaotik78 is offline   Reply With Quote
Old 02-11-2010, 08:39 AM   #5
GEE-OTTO
Scooby Specialist
 
Member#: 201277
Join Date: Jan 2009
Chapter/Region: MAIC
Location: Northern VA
Vehicle:
2008 08 QSM 5MT LGT
QSM

Default

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.
GEE-OTTO is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
08 2.5i UEL Headers Subarudave09 Normally Aspirated Powertrain 10 10-20-2010 06:25 PM
FS: 07 2.5i EL Header/Cat/cat pipe 02darkRS Engine/Power/Exhaust 4 05-08-2010 10:00 AM
07 2.5i stock header and midpipe. sittinsideways Engine/Power/Exhaust 1 03-21-2010 08:28 PM
WTB - 06-07 2.5I stock header. or i have a wrx manifold for trade Loomin VIC Private Classifieds 3 12-18-2009 04:50 AM
EL vs UEL headers and exhuast questions 06-07 2.5i Sir-Knight Normally Aspirated Powertrain 9 11-24-2006 08:11 PM

All times are GMT -4. The time now is 09:56 PM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2024 Axivo Inc.
Copyright ©1999 - 2019, North American Subaru Impreza Owners Club, Inc.

As an Amazon Associate I earn from qualifying purchases.

When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission
Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.