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Discussion Starter · #1 · (Edited)
I was discussing in the frankenstein 2.2/2.5 thread about putting the 2.5 in my car without doing the 2.2 head swap, I was under the impression that was the only way to get the 2.5 to work in my car.

this will be my first subaru swap (I am no stranger to engine swaps, in fact I have a patent on Lexus 1UZFE 4.0 V8 motor mounts that bolt it right into a Toyota 4Runner/Truck- replacing the 3.0 or 2.4) so most aspects of a swap arent an issue for me, what I want to know is to bolt the 2.5 in what else needs to be addressed? can I just bolt my 2.2 throttle body on the 2.5 intake as well as sensors, or use existing sensors?

thanks for any advice, this was a free car (I paid scrap metal price for it, had a rod through the block) I was going to build a higher compression motor with 2.2 heads, but for now until I can put some money into the heads and other performance parts I will settle for the 2.5 stock.

yes, I did do a search on doing the 96 OBDII, I didnt find a thing on it.
 

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97 OBS
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You can run the ej25 on ej22 engine management no problem.
Some stuff may need some custom fab but its not too much at all.

Run the ej25 longblock and ej25 intake.
Remove the ej22 wiring harness from the ej22 intake and swap onto ej25 intake, route all vacuum like your ej22 would be.
You may be able to swap the fuel rails or you can just block off the idle assist valve of whatever it is on the front pass side of the ej25 intake.
For the injectors you can just trim the ears and rotate the plug on the ej22 wiring onto the ej25 injector (you want to match where the yellow wire goes).
You will need to take off the timing cover and compare by feel the back of the drivers side cam gear and feel the nubs on the back and make sure they match, otherwise you need to swap the pulley.
You also need to compare the crank gear marks as well, some years auto vs manuals are different from what I have read.
If you have and IACV (idle air control valve) you may need to remote mount it and run coolant lines from your throttle body to it and find a place on the ej25 intake to plumb it into after the throttle body since it lets in air to adjust your idle based on temp readings from the coolant running to it.
EGR can be a pain, it really depends on if your car is an auto or if the donor is an auto.
But you can drill/tap the head and intake if you need egr and the ej25 doesn't have it.
Or you can also block them off if you don't need it and the ej25 has it.

Check out the last page on my member journal, I did this as my first Subaru swap (or pulling a subaru engine for that matter) mostly at night after midnight outside with hand tools on a gravel driveway in freezing weather. Had to pull both engines from cars to do it and got it done in mostly 2 nights and spent the next 2 nights being lazy and taking my time routing my iacv.
I would suggest trying to setup the intake off the engines side my side to compare.
Read about the emissions systems for both year engines and put everything from the ej22 into the ej25 intake.
Also try to do as big of an iacv connector into the ej25 intake as you can, I have some issues on startup for the first 10-20secs because my hose is too small and does not let enough air past the closed throttle when at idle.

If you have any questions feel free to ask away.

Good luck!
 

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opendeck251+stiInternals
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Better yet, if your 96 has the IACV on the throttle body, you can just swap over a complete SOHC EJ25. The easiest would be to just use your EJ22 heads, on an EJ25 block. But if you have access to EJ25 heads use them.


~Josh~
 

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Discussion Starter · #6 ·
thanks for the replies everyone.

your advice helps me familiarize myself with the ins and outs of the swaps that you have already done and saves the headaches and panic when I get into pulling and swapping these this weekend.


I dont believe (as someone posted) that the 2.2 intake will bolt up to the 2.5.

as far as swapping my 2.2 heads on, I will build a separate engine using the later 2.2 heads (phase II) for now i just want to get it on the road and have a little fun with it.

I have a EJ251 out of a 01 Forester that I picked up with a salvage title (500 bucks, 118,000 miles) I will part the rest of the car out to recoup some of my money and purchase a new clutch (any suggestions? just a good clutch, nothing outrageously priced!!) I will buy a set of the Borla replica headers as well (so far everyone has had good luck with them from what I have read, correct?)

will the 2.5 put out as much HP as it did in the original car it is out of, being ran on the 2.2 ECU? just curious.
 

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yep. you heard me.
‘18 E63s AMG wagon & 10 Subarus
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phase 2 wasnt until 98 production year for anything. so basically some 98 cars and everything 99+.

there WAS the issue of single and dual port for the EJ22, it was dual port up until 96 then it went single port until the EJ22 died out after 01. which is my 99 EJ22s are rare and weird because they are phase 2 and only in the 99 legacy L and 99-01 impreza L/OBS

i think i'm mostly right on this, but there may be some minor corrections
 

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Discussion Starter · #15 ·
So I remove the flywheel from the 2.2 and replace the starter gear for the 2.5 auto (replace rear main seal while inside of it all of course) with the flywheel from 2.2?

I read somewhere about the starter bolt needs to be addressed?
 

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97 OBS
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So I remove the flywheel from the 2.2 and replace the starter gear for the 2.5 auto (replace rear main seal while inside of it all of course) with the flywheel from 2.2?

I read somewhere about the starter bolt needs to be addressed?
Basically you unbolt the pressure plate from the back of the flywheel and the clutch disc then you transfer the flywheel with everything over to the other engine.
The flywheel bolts on the manual vs the flex plate bolts on the automatic are different lengths so use the ones from the manual when you swap it over (the 6 or so bolts that go into the crank)

I would definitely replace the rear main seal and reseal the oil separator plate also (replace if plastic)

If you change your clutch make sure you change your throw out bearing and the pilot bearing as well (mine rolled nice and fine but makes noise anyway)

Depending on your transmissions mileage you may also want to look into a snout kit (the input shaft and the throw out bearing can have issues over time with excessive play from the aluminium casing wearing down) also a big issues with some of the 5mts is the nut on the back of the main shaft inside the case was not torqued correctly from the factory and can cause premature wear of the main shaft bearings in the trans and give you a wonky input shaft (I think that is the noise mine makes 24/7 and has since 2005 lol)

Also for the starter I am unsure about what bolt you are talking about the needs to be addressed. If you are running the same trans and flywheel then the starter should mount and be the exact same as you had in there before.

One thing I would check is the brass starter bushing. Look into the trans bellhousing from the starter hole and you will see a little hole in the trans casing with a brass sleeve in it, that is the starter bushing. When the starter solenoid clicks forward to engage the flywheel the end of the starter rests in the hole on the brass bushing, over time it wears and can give you starter issues. Just make sure its not all gouged up and misshapen and I think it should be good.

Also since you are putting in an ej151, there are these seals for the spark plugs under the valve covers and they commonly leak (they call them trumpet seals sometimes) but I would read up on those and change them and the spark plugs and valve cover seals while the engine is out (easier without the frame rails being right next to it lol)

I would also suggest you look around on the net and find yourself a FSM for your Subaru (Factory Service Manual) or at least grab a crappy haynes manual or a basic guide, it can help out.
Also look for exploded parts diagrams too, they help a lot.

Good luck!
 

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Discussion Starter · #17 · (Edited)
thanks, I feel like such a noob- first subaru.
fabrication and engine swaps are not a big undertaking for me but who wants to learn as you go when its been done before (subie 2.5 into 2.2)
I appreciate your info (Li-scooby) and have printed off tidbits from your journal when you did this swap.

I ordered and exedy oem replacement clutch kit for it and some ebay borla reps (trying to keep this really low cost) your tips will save me from tearing into this again any time soon. the trans has 131000 miles on it so anything to do preventative maintenance while I am in there will be a big help. much appreciated.

I do have a set of EJ25d heads for sale if any1 is looking just FYI ( I cant post in for sale section yet...)
 

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96 Impreza wagon, Flat black
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Im Doing the exact same swap right now. the single port 2.2 intake will not bolt up to the ej251 heads in my case. the bold pattern is still a stagger bolt pattern, but the its a different offset and runners are much larger on the 2.5. Throttle body wont swap either due to the idle assist ports on the ej22. And fuel rails are completly different. As well as the IACV is going to be a pain to make.

I've about decided to just keep and the same heads and intake that are in the car now and just replace to block with the ej251. I'm sure I'll loose some power due to the heads but itll be a much better block with higher compression from what I've read. Searching everywhere I can to find somebody that has already done this exact swap and made it work.

Are you running into the same things as I am?
 

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Discussion Starter · #19 ·
you will actually gain soem power from the compression boost but lose a little top end due to less flow with the 2.2 heads.

from what everyone is saying you can make a bracket for the IACV? I will know more later today. I am working on all of it right now
 

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Discussion Starter · #20 ·
So after wrenching today I have 1 question ( I did search) can I use an 2000 EJ22 throttle body to retain the use of an IACV using the three wire set up on mine? I want it to idle the way it is supposed too and not by turning up the idle screw.
 
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