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1998 EJ25 engine and tranny swap into 2000 EJ22 OBS


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11 replies to this topic

#1 s'ko

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Posted 10 April 2008 - 01:06 PM

from what I read, the ej18 is not going to work w/o some issues.

Found a EJ25 for a good price w/a 5spd tranny.
my tranny's synchros were going out so it's a good time to do both.

Here are a few questions.

1) EJ25 is that pretty much a plug and play for the EJ22 ECU?

2) The new tranny has a hydraulic clutch cable do I need to retrofit the hydraulic system into my car?

Thanks for the input.

BW

#2 mellow65

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Posted 10 April 2008 - 03:20 PM

if it's a dohc ej25 then it should be more plug and play. just think of the outbacks to ej22 swap but in reverse. you do still need a duel port header. if it's a sohc that's a whole different ball of wax. i put one in my 90 legacy, but i have no IAC. it's just something I live with because it's my rally car and cold starts are the least of my worries. it's just because the sohc ej25s have the IAC on the throttle body and the ej22s have them on the intake manifold. the IAC on the sohc ej25 don't even have close to the same plug (mine didn't because it was OBD1, may be different on OBD2 ej22s).

there is rumor that some JDM wrxs had intakes that bolt onto the sohc heads and have the IAC mounted on the intake. I wasn't ever able to find one and check for myself. The other path to try is to use a ej18 throttle body because it has the IAC mounted on the throttle body. I was going to try this route but I never could find one to mount on my car. The plugs are the same on the ej18 IAC and the ej22 IAC I just don't know if the computer would run it.

As for your tranny, i have found that the NA trannys (and maybe turbo, just don't know) will take your cable clutch shift fork. i had a cable set up on a 03 RS tranny in my 90 legacy and it worked fine.

if you do get a 2.5 motor you might just think of doing the 2.5 block 2.2 head hybrid motor. lots of people have done that and seem to be real happy with it. that is if your heads are in good shape. but even to have them redone i found someone here local that would fully redo both for under $150, so it's not that bad to have them redone.

good luck:)

#3 s'ko

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Posted 10 April 2008 - 03:46 PM

if it's a dohc ej25 then it should be more plug and play. just think of the outbacks to ej22 swap but in reverse. you do still need a dual port header.


It's a DOHC motor. and comes with a set of Borlas.

As for your tranny, i have found that the NA trannys (and maybe turbo, just don't know) will take your cable clutch shift fork. i had a cable set up on a 03 RS tranny in my 90 legacy and it worked fine.


found a thread by legacy777 on nasioc on how to get the fork to work

if you do get a 2.5 motor you might just think of doing the 2.5 block 2.2 head hybrid motor. lots of people have done that and seem to be real happy with it. that is if your heads are in good shape. but even to have them redone i found someone here local that would fully redo both for under $150, so it's not that bad to have them redone.

good luck:)

thought about going that route, but this is a complete EJ25 that was taken out of a 1998 RS to do a 05 STi swap into. There is no problems with the motor. I will be taking the heads off and replacing the head gaskets to make sure they don't pop.

Sounds like this is going to be the new engine for my OBS. :banana:

#4 s'ko

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Posted 10 April 2008 - 04:05 PM

MORE good news.

According to the previous said that he has already done the head gaskets.

woo hoo.. OBS will rise again.

Now I have a spare EJ22 n/a block I can rebuild and play with. looks like an EJ22 will be residing in my BRAT in the near future.

BW

#5 grossgary

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Posted 10 April 2008 - 06:21 PM

awesome - new headgaskets!

AH!!!! you need to remind people of the years of the stuff you're working with. there are significant changes through they years and when doing a swap it's not enough to say "EJ22" or "EJ25".

as long as SOHC and DOHC EJ25 intake manifolds are interchangeable that's good (and i think they are).

the bellhousing changed around 1999 - so you'll be putting a 4 bolt to an 8 bolt i believe. but that can be worked around if that's the case.

most significantly because this is a 2000 you're going to have "special considerations" that don't apply to earlier EJ22's...hence my remark about verifying what you're doing earlier. i think you'll need to retain the EJ22 cam pulleys, or at least the one with the sensor triggers on it. normally you'd swap all the pulleys over if it was SOHC to SOHC...but being DOHC i'm not sure.

#6 mellow65

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Posted 10 April 2008 - 06:45 PM

as long as SOHC and DOHC EJ25 intake manifolds are interchangeable that's good (and i think they are).


they aren't, they moved the bolt holes.

#7 s'ko

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Posted 10 April 2008 - 07:14 PM

they aren't, they moved the bolt holes.


I am getting the complete engine. So I will have intake manfold, injectors and all of the other fun stuff that comes on an 1998 EJ25.

BW

#8 grossgary

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Posted 10 April 2008 - 08:05 PM

i don't know that the 98 electronics are compatible with the 2000 stuff. do you know if the 98 stuff (Phase I) will plug in and work with the 2000 (Phase II) stuff? there's not much information on doing swaps across Phase I and Phase II, so it's a mix of related knowledge to get you there. what i'm sure of is that it is not like other EJ swaps.

swapping engine and trans sounds like a great plan. you'll just need the rear differential to match since it'll be a different gear ratio. the RS should probably be a 4.44 gear ratio, so you'll need a 4.44 rear diff to swap in too. actually i think i have a 4.44 rear diff i'd sell if you need one.

the 2000 vehicle is not going to be compatible with the RS EJ25, i know that for sure that it will not be a drop in and plug and play scenario.

not sure if swapping ECU's would work (it does on 1998 and earlier...not sure about 2000's). if the wiring didn't change this will work. i have a DOHC ECU i could sell if that's the case.

all you need to do is look at the wiring diagrams for a Phase I DOHC EJ25 and a Phase II SOHC EJ22 (or Phase II SOHC EJ25 will be the same). i have the former but not the later. i'll send it to you if you need it, or post here.

no matter what you do the DOHC cams will not work with your 2000 EJ22 vehicle....that's why trying the EJ25 DOHC ECU might be worth looking into. then everything becomes plug and play.

#9 grossgary

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Posted 10 April 2008 - 08:07 PM

[quote name='mellow65']they aren't, they moved the bolt holes.[/QUOTE]
great information mellow - i was wondering... that rules out the easy solution.

[quote name='s'ko]I am getting the complete engine. So I will have intake manfold' date=' injectors and all of the other fun stuff[/QUOTE']the issue isn't whether or not you got the intake manifold...intake manifolds are everywhere and easy to find. what matters is that the electronics are compatible between these two engines.

having the intake manifold with the engine doesn't mean anything. i can go buy hundreds of different motors, ford, dodge, ferrari, with intake manifolds but if the wiring and plugs don't match up it doesn't matter. so now you hope the electronics didn't change.

hold on to your EJ22 intake wiring harness after you pull the motor and try to keep it in good condition just in case you have to try and install it onto your EJ25 intake manifold.

#10 mellow65

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Posted 10 April 2008 - 08:08 PM

I am getting the complete engine. So I will have intake manfold, injectors and all of the other fun stuff that comes on an 1998 EJ25.

BW


i got that i was clearing it up for grossgary.

this should be a pretty strait forward swap unless they changed harness plugs along the way.

also that should be a fun little car after you are done. i love my ej25 powered legacy and got to think a 2.5 obs would be even better. one thing that i ran into was the grade of fuel i had to run. because of the bump in compression and the fact that ej22 ecus have the second steepest ignition curve (only to be out done by the ej18) i had some detonation in the higher rpms. the knock sensor took care of it but it also sucked my power in doing so. my solution was to run super and it took care of it. but i'm using mine in a rally car. with normal driving i didn't feel any loss of power.

#11 mellow65

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Posted 10 April 2008 - 08:20 PM

great information mellow - i was wondering...

that means you can't bolt your EJ22 intake to the EJ25. the issue isn't whether or not you got the intake manifold...intake manifolds are everywhere and easy to find. what matters is that the electronics are compatible between these two engines.

if the intake manifold bolts up (which we now know it doesn't), then it's very easy....just bolt your Ej22 intake onto your EJ25 engine....but we just found out that's not possible.

so now you hope the electronics didn't change. having the intake manifold with the engine doesn't mean anything. i can go buy hundreds of different motors, ford, dodge, ferrari, with intake manifolds but if the wiring and plugs don't match up it doesn't matter.

hold on to your EJ22 intake wiring harness after you pull the motor and try to keep it in good condition just in case you have to try and install it onto your EJ25 intake manifold.



but the nice thing is subaru followed the K.I.S.S. "keep it simple stupid".

so many things are interchangeable on the ej series motors. this is why it was crazy easy to swap a 99 motor into my 90 legacy. sure there were a couple little things to overcome but nothing was crazy. even if he has to pull the harness off of his 2.2 and snake it onto the 2.5 it still is easy. that part of my swap took all of 5 mins.

or even if they changed all the plugs and sensors make it work. the only part of the 99 ej25 electronics i am running on my car is the injectors. nothing else. ever other sensor and plug is strait off a ej22. and i only had to do that because i had a phase 2 ej25 and they changed damn near every plug and wire between the phase 1 and 2 ej25.

#12 s'ko

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Posted 11 April 2008 - 01:30 AM

Thanks for all of the info.

I think that I am going to go the route of taking the EJ22 intake harness off and using it on the EJ25. I mean all of the sensors should be there, cam angle, crank angle, knock etc. It's just getting the signal to the correct pin in the ECU. If I use the EJ22 harness I will not have to play with wires, I will just have to make sure that the appropriate connectors are plugged into the sensor. I have diagrams for both engines. I need to go over them and compare the two. Hopefully this will be a one day, at most a two day weekend job, b/c I am going to borrow a neighbor's garage space to do it.

Will keep you posted




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