Jump to content
Ultimate Subaru Message Board

95 impreza 1.8-2.5 dohc or sohc


topherwh
 Share

Recommended Posts

no, it won't work.

 

you have options. the only way to make this plug and play is to get an EJ22 and bolt your EJ18 intake manifold to it (you can't do that with the EJ25 as the manifolds aren't even close).

 

you would want to make sure it's an EJ22 with EGR (assuming your EJ18 has EGR, i'm guessing it does).

 

the good news is the EJ22 is a better motor than the EJ25. if that's news to you search here or google for "EJ25 headgasket" and read all about it.

 

the only option you have for an EJ25 is attempting to install your EJ18 intake manifold wiring harness onto the EJ25 intake manifold. based on your question i'm assuming you're looking for an easy swap, this option is not the easy one you're looking for and will entail some hurdles because the EJ18 is a goofball in some ways.

 

of course you can install the EJ25 with the entire EJ25 wiring harness, but it doesn't sound like you're looking for all that.

Link to comment
Share on other sites

i definitely appreciate the advice guys, i have herd about the 2.5 head gaskets, and have experienced it first had, i had a 98 forester that blew two of them. will the 2.2 give me a noticeable power increase, and the 1.8 intake manifold just bolts right up to the 2.2 heads?

Link to comment
Share on other sites

the only option you have for an EJ25 is attempting to install your EJ18 intake manifold wiring harness onto the EJ25 intake manifold. based on your question i'm assuming you're looking for an easy swap, this option is not the easy one you're looking for and will entail some hurdles because the EJ18 is a goofball in some ways.

 

why would you put a ej18 intake on a ej25 when you can use the ej25 intake and an ej18 throttle body.

 

the intake wiring had to take me all of 30 mins to do and that included zip tieing everything in place. it doesn't get much easier then that.

 

there is no large hurdles to overcome just some little ones.

 

but for simplicity yes just putting a ej22 under the ej18 intake would be the easiest, but why take the easy route. :grin:

Link to comment
Share on other sites

will the 2.2 give me a noticeable power increase, and the 1.8 intake manifold just bolts right up to the 2.2 heads?
yes on all counts. you can compare hp and torque numbers if you'd like, but the EJ22 gives much better power compared to the EJ18. faster, pulls loads, towing, passengers, weight, interstate mountain driving...all of that noticeably better. the EJ22 is a perfect fit because it makes the car much nicer to drive but is just as reliable as the puny EJ18. the EJ25 is nice too, but it's not fast so the reliability issues aren't worth it to me. it's still just a 165hp motor.

 

i didn't know the EJ18 throttle body bolted up to the EJ25 intake and this guy didn't seem to interested in much more than bolt in deal, but sounds easy enough to me.

Link to comment
Share on other sites

yes on all counts. you can compare hp and torque numbers if you'd like, but the EJ22 gives much better power compared to the EJ18. faster, pulls loads, towing, passengers, weight, interstate mountain driving...all of that noticeably better. the EJ22 is a perfect fit because it makes the car much nicer to drive but is just as reliable as the puny EJ18. the EJ25 is nice too, but it's not fast so the reliability issues aren't worth it to me. it's still just a 165hp motor.

 

i didn't know the EJ18 throttle body bolted up to the EJ25 intake and this guy didn't seem to interested in much more than bolt in deal, but sounds easy enough to me.

 

stuff to think about also when swapping to the 2.2, (because i'm going to do that same thing here in a few weeks and i have been making mental notes of what i need to do) 1, the 1.8 throttle body has a smaller throttle plate then the 2.2, and 2 the 1.8 exhaust is ridiculously small.

 

what i'm going to do is run the 2.2 intake with throttle body and put the intake wiring harness from the 1.8 on it and i have an exhaust from a legacy i'm going to put on also. not sure if the computer will be happy with the TPS and IAC from the 2.2 but we will see.

 

and the ej25 just got a bad wrap from all the head gasket issues. i had that phase 2 ej25 in my rally car and beat the snot sh|t out it and it never had one issue. but i also planned ahead and redid the head gaskets with some quality stuff and did it right the first time so i didn't need to do it again.

 

also on power, the ej25s were horribly choked from the factory, put a larger exhaust and some lumpy cams, and that motor was a little monster. my legacy was pretty close to stock wrx fast, that's not to bad for a "just a 165hp motor".

Link to comment
Share on other sites

i was also wondering what the newist year motor i could drop in there is. again thanks for yawls help

 

ej25 or ej22?

 

my ej25 was from a 99 forester. but i have heard that later years changed the cam and crank triggering marks so it wouldn't be compatible with the older ECUs. but not really sure what year they did that in.

 

as for the ej22 i think they were all the same (basically) till the end of them.

Link to comment
Share on other sites

the later EJ22's differ as well. the EJ22's went through Phase II changes like the EJ25's - around 1999 (though that was a mixed year) - by 2000 all are Phase II and not easily interchangeable between phases.

 

the 99 Foresters got the first batch of the "newer" Phase II EJ25's with SOHC, was it a SOHC that you had? if you swap throttle body and wiring harness, maybe it doesn't much matter?

 

no one ever said the EJ25 is a bad motor or that every single one will give bad experiences. so there are plenty of anecdotal "good" experiences, but you really did it the best way.

 

the only reason i mention the EJ25 issues is that some (many) folks put $1000-$2,000 into something and can't afford that kind of repair soon after. so it's good to know upfront. then they can try and find one with new headgaskets or did what you did. and, frankly i think the JDM's are a bad option. better to just buy a local one and have new gaskets put on it.

 

one issue isn't the car. anyone putting that kind of money in a vehicle should not be in a position where a head gasket repair puts them over the edge financially, but this isn't a financial board and that's how most americans live.

Edited by grossgary
Link to comment
Share on other sites

at this point I'm thinking i might just build an engine for this thing from the ground up, and am now currently wondering how easy it is to stick cosworth heads onto a suby block. if any one has any input on building from the ground up i would much appreciate it.

Link to comment
Share on other sites

  • 4 weeks later...

The Phase 1 EJ25's (DOHC) tend to develop a bottom end rattle over time which sounds more like a wrist pin rattle than anything else and I don't know of any that have been terminal BUT there is always that annnoying and worrysome rattle/knock. I drove mine for several thousand miles without any problems before I broke down and replaced it with an 05 shortblock and 1995 JDM Hyd valve DOHC heads. They also had head gasket weaknesses, as did the early Phase 2- SOHC's...The later 03?-up have pretty much been trouble free, I believe.

 

If you decide to go with the EJ25, I'd use a newer SOHC short block with 98-99 DOHC heads bolted up...uses the early DOHC EJ25 harness/ecu and retains the early DOHC intake manifold but with the bottom end reliability of the SOHC and CR in the 10:1+ range so a bit more power.

 

Only real "mod" is you have to elongate the intake manifold bolt holes by about 1/16" since with the new "steel shim" head gaskets, the heads will actually sit that much closer to each other....OH yeah, you will also want to exchange the DOHC 10MM oil pump onto the SOHC inplace of the stock 6 or 8MM oil pump used stock on the SOHC.

 

Is what I built for my 98 RS and made a world of difference with a short ram intake and OBX EL headers + 2.25" full exhaust...very NICE for a "stock" naturally aspirated subaru engine and should be pretty eye-opening if compared to the original 1.8...I'm guessing somewhere in the 185-200 crank HP range for my build using the JDM heads and bolt-ons noted above.

 

L

Link to comment
Share on other sites

  • 4 weeks later...

I put did a sohc 2.5 into my 96 1.8 car a while ago. Kept the 2.5 manifold with 1.8 throttle body. Fairly easy swap, drove the car in saturday with the 1.8 and drove it home that night with the 2.5.

 

I have more info and pics on my site http:www.fakewrx.com

 

Needed to change the injector plugs, since the phase 2 motors use different injectors, but as long as you get the plugs on the motor you can splice them into the wiring harness.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...