Subaru Liberty 2.5i exhaust and facelift myths demolished

Posts specific to the 2.5 litre NA engine

Subaru Liberty 2.5i exhaust and facelift myths demolished

Postby Horizon » Tue Jun 08, 2021 2:29 pm

Alright this is just a big list of information I've figured out over the past few years whilst trying to modify my pre-facelift 2005 Subaru Liberty 2.5i safety pack 5mt, in arctic white pearl 36j.
Info is generally pretty thin about 2.5i's on the internet (if its even in english) thanks to subaru making about 45 different models of gen 4 Libertys/Legacys, including all the little differences between regional models. But thats what makes these cars fun :). Most of this is just off the top of my head so please correct me if Im wrong. cheers

Hopefully this helps some P platers out there.

Heres the yacht as of early 2021

Image

Image
Last edited by Horizon on Tue Nov 16, 2021 1:41 pm, edited 2 times in total.
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Re: Leaky Boi Liberty 2.5i R&D

Postby Horizon » Tue Jun 08, 2021 3:06 pm

Facelift Differences

Alright kicking it off there are quite a few small differences between pre and post facelift models, sometimes parts will only fit one or the either (usually just cosmetic, interior or exhaust parts).
These differencs can be important when buying mods (usually it doesn't but still good to know). Here are the main differences you should know straight up.

Model Years Gen 4
Going off the build date because MY can be a bit gangstar.
Late 2003- Mid(?)2006 are Pre-Facelift
Late 2006 - Early 2009 are Post-Facelift

Engine Code
Pre-Facelift 2.5is have EJ253 engines.
EJ 253s are only found in Outbacks and Libertys from what I can find.
Post-Facelift 2.5is have EJ253 engines. Very minor changes like tumble generator valves to reduce emissions on startup.
EJ253s are also found in similar years Foresters, gen 5 Libertys and some Exigas.

Transmissions
Manual: the 5 speed in the 2.5is are the same across the facelifts.
Auto: Not 100% sure but it appears the EAT is slightly different between facelifts.
Last edited by Horizon on Fri Feb 18, 2022 3:01 pm, edited 1 time in total.
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Re: Leaky Boi Liberty 2.5i R&D

Postby Horizon » Fri Jun 18, 2021 1:33 pm

Facelift Differences Exhaust

Aight getting into the mysterious stuff, accurate exhaust diagram for 2.5i's are apparently forbidden on the internet?? Most online parts stores don't even list the correct diagram :)

Differences
Both the Pre-facelift and Post-facelift share the same mufflers (including other trim levels), im unsure whether the 2.5i midpipe/y-pipe is the same as other trims, but considering they are different between Pre-Facelift and Post-Facelift I would think they are not.
The midpipes are relatively the same between facelifts, except the pre-facelift is slightly longer at the front. J-pipes and headers are completely different between the facelifts but are interchangable with some work.
o2 sensors on the Pre-Facelift are located at the front of the engine on the J-Pipe and at the rear of the engine also on the J-pipe.
o2 sensors on the Post-facelift are both located at the front of the engine on the header.

Interchangeability
Hangars are the same across facelifts so it is possible to swap everything from the header to the midpipe/Y-pipe without modification (except for the use of o2 sensor extension cables).
To change headers and J-pipes between facelifts you can get away with using either midpipe but you would need to either lengthen or shorten the front of the midpipe to make it work.
Just changing headers would take a lotttt of work, and you could end up coming out of it with an extra catalyctic converter, true econobox spec. CEL might get a bit fucky if your unlucky as well.

These diagrams apply for the standard 2.5i's and not the weird ones like the californian PZEV model.

Pre-Facelift
Seemingly hidden from public eyes this was taken from a subaru technician manual and edited slightly.
Image

Post-Facelift
This is what will come up when you search for a gen 4 2.5i exhaust diagram, even when you put in Pre-facelift years. Dont be a dumbass like me and order parts that suite this setup when you have a Pre-facelift and then only realise when they get delivered they dont fit :)
Image
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Re: Leaky Boi Liberty 2.5i R&D

Postby Horizon » Fri Jun 18, 2021 1:36 pm

Aftermarket UEL Headers Fitment

Alright if your going for a UEL (un equal length) header (not sure why you wouldn't with a 2.5i) there is only 1 off the shelf option, an EL (equal length) header is a little easier to find regardless heres all the info I have found.
For reference I have an infernofab uel header and Pre-facelift J-pipe ready to go on my car, in hindsight not the cheapest route haha but it requires the least amount of custom fabbing.

Available Headers
- Infernofab.com makes direct bolt on headers for Post-facelift models, they also work well with Pre-facelift but require a bit of work to get fitted
- There are various oem style EL headers for Post-facelift available online but none are performance headers or have higher flowing cats
- Rallisport used to make direct bolt on headers, I have rarely seen some for sale on ebay second hand. Not 100% sure but I assume they bolted on to Pre-Facelift


Pre-Facelift

There aren't many off the shelf options to put UEL headers on a Pre-Facelift. Listed below are the different ways you can setup the car with UEL headers.

- Infernofab UEL 2.5i header + Infernofab adjustable cat delete J-pipe. The only direct bolt-on option. Low chance of CEL (cat delete is post sensors)
- Infernofab UEL 2.5i header + Post-facelift J-pipe + rear o2 extension cable. Requires the new J-pipe to be shortened slightly (refer to above post about J-pipe lengths). No CEL
- Infernofab UEL 2.5i header + custom J-pipe. As there is a cat in the Post-facelift style setup you could either delete it or add in a high-flow. low chance of CEL
- Full custom uel header. Obviously compatible with existing header, this is actually a much better option then it appears as there is no cat or o2 sensor it should be pretty simple to do. No CEL
- Modified impreza 2.5rs or liberty gt header + custom J-pipe. Requires a good bit of custom fabbing. High chance of CEL.


Post-facelift

If you own a Post-facelift your in luck, its much easier to put UEL headers on your car. And Im not jealous... at all...

- Infernofab UEL 2.5i header. Thats it. Thats all you need. No CEL
- Infernofab UEL 2.5i header + Infernofab adjustable J-pipe with cat delete. Low chance of CEL (cat delete is post sensor)
- Full custom uel header. Obviously compatible with existing header. A bit trickier then the Pre-facelift as you would need to add a cat and 2 o2 sensors on either side to avoid CEL. Chance of CEL
- Modified impreza 2.5rs or liberty gt header + custom J-pipe(?). Requires a good bit of custom fabbing. There is a possibility that you can use the stock J-pipe but change the flange on it a bit, im not 100% sure tho. High chance of CEL.
Last edited by Horizon on Thu Jul 01, 2021 1:51 pm, edited 1 time in total.
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Re: Leaky Boi Liberty 2.5i R&D

Postby Horizon » Fri Jun 18, 2021 1:37 pm

Aftermarket exhaust fitment placeholder///
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Re: Leaky Boi Liberty 2.5i R&D

Postby Horizon » Fri Jun 18, 2021 1:40 pm

Aftermarket Suspension fitment and the dreaded saggy butt

Factory Suspension
The 2.5i shares the same suspension setup as 2.0r, GTs and 3.0r Libertys (sedan and wagon suspensions are identical) and does not share setup with outbacks, spec Bs and Tuned by STI (but it is possible to swap entire suspension setups between these models and 2.5i)
The 2.5i comes with standard KYB shocks and JDM spec top hats
Factory alignment is Front: ~-0.5°- Rear: ~-1.0°

Saggy Butt :shok:
2.5i's feature some of the most aggressive "saggy butt" of all liberty's, this is where the front of the car appears higher then the rear which "sags"
Last edited by Horizon on Mon Nov 22, 2021 9:11 pm, edited 1 time in total.
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Re: Leaky Boi Liberty 2.5i R&D

Postby bigBADbenny » Fri Jun 18, 2021 6:35 pm

So good! Awesome post.
Lotta dedicated fans of these models here.
Ours is prefl 2.5i 4eat and with a few upgrades is a screaming bargain for an affordable and very enjoyable tourer. :good:
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Re: Leaky Boi Liberty 2.5i R&D

Postby bigBADbenny » Sat Jun 19, 2021 2:17 pm

Back in the day, Hyrax’s postfl 2.5i was one of the most enhanced 2.5i, and an inspiration to all.
Here’s his member profile:
viewtopic.php?f=10&t=15482
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