EJ22 SOHC to EJ25 DOHC engine swap

[EVOthis]

hello all....i have a 1996 legacy with a 5 speed trans and a 2.2 SOHC engine.....I was looking into swapping in a 2.5 DOHC non turbo.....just wondering if i would need to do anything special (does the ej25 bolt right up to the ej22 trans?...how about the wiring harness? just lookin for a little bit more power

[s'ko]

IMO the HP gains from the two would not be worth the effort to do the swap.

 

I would do it if you had a dead EJ22 and a free or really cheap EJ25 that you can get your hands on.

 

tranny will bolt on w/o a problem, the wiring harness will have to be either modified or you can use a trimmed down EJ25 harness.

 

Let me know if you need diagrams.

 

BW

[EVOthis]

well i have a pretty bad misfire that i am almost certain is the valve problem....besides the 2.2 has around 190,000 on it. how hard would it be to throw an 04' sti engine and trans in my 96 legacy?......

[Manarius]

well i have a pretty bad misfire that i am almost certain is the valve problem....besides the 2.2 has around 190,000 on it. how hard would it be to throw an 04' sti engine and trans in my 96 legacy?......

Wiring would be a PITA. At least, as far as I know.

[idosubaru]

waste of time and money going with an EJ25 swap. the hp difference is miniscule really. it's like going from slow to not as slow, seems like a lot of effort and time or money for an engine swap and then you'll end up with a less reliable engine anyway. you are familiar with all of the EJ25 head gasket issues right?

 

if you have a cylinder misfire - first bet is to make sure it's not something simple. cylinder misfire is the most common ECU code i see on EJ engines. and so far it's always been ignition wires, simple. for EJ engines you want to make certain you have Subaru OEM spark plug wires (or magnecor) and NGK plugs. they are not very forgiving motors when it comes to ignition components.

 

if you're still buckwild about an engine replacement - get a used EJ22 (far cheaper and more reliable than the EJ25) and put a turbo on it. they are good for a few pounds of boost without any major modifications. you'll get more and cheaper power than an EJ25 and more reliable as well (assuming you can take care of a turbo and aren't tempted to push the limits and blow it up - good luck with that!).

 

the STi swap would be fantastic - tons of work and it won't be straight forward, lots of wiring, ECU and other issues to work out, but very possible.

[s'ko]

throw an 04' sti engine and trans in my 96 legacy?......

 

now were talking...

 

I would do some homework and see what the engine replacement laws are in your state and the emissions testing laws.

 

You might be able to get away with an JDM motor and drivetrain for about 1000 or so, maybe 1500 w/shipping.

 

Eastcoastswappers is in MA and they can probably get you the motor.

 

Have fun and take pictures.

[subaru360]

IMO the HP gains from the two would not be worth the effort to do the swap.

 

I would do it if you had a dead EJ22 and a free or really cheap EJ25 that you can get your hands on.

 

tranny will bolt on w/o a problem' date=' the wiring harness will have to be either modified or you can use a trimmed down EJ25 harness.

 

Let me know if you need diagrams.

 

BW[/quote']

The wiring won't need any work for this swap. Everything will plug in and work. You can even run it on the EJ22 ECU.

[cdenora]

IMO the HP gains from the two would not be worth the effort to do the swap.

 

I would do it if you had a dead EJ22 and a free or really cheap EJ25 that you can get your hands on.

 

tranny will bolt on w/o a problem' date=' the wiring harness will have to be either modified or you can use a trimmed down EJ25 harness.

 

Let me know if you need diagrams.

 

BW[/quote']

 

i got a ej25 engine from a guy in the internet and got the engine without the wiring harness , i got the computerfrom a forester99 but need the wiring harness , do you have an idea where i can get one ? I guess i will need the diagrams to trim it down for a sand rail please help

[tturnpaw]

Didn't realize thus thread was old. Sorry guys!!!!

 

 

This is where I chime in. First you can use your 2.2 harness and ecu to power the 25. It's all a phase 1 so you're good to go there. To swap in an engine that's 00+ that's phase 2. Stay away from that unless you have lots o money to throw down on endless parts.

 

Ok so to run the 2.5 on your 2.2 harness all you need is to swap out the iac and throttle body on the 25d intake manifold. Use the 25d injectors basically keep the engine complete. And done. No cel runs perfect.

 

As for the 25d's head gasket issue, they fixed it in late 98, and 25d's are just as reliable. If you really wanted get arp head studs and you won't ever think about an issue until routine maintenance comes. The only thing about dohc is that you would be swapping to a interference engine. All Subaru dohc are interference. The valves can crash into each other. Given, they have a much better timing belt tensioner that they still use to this day on sti's so if you replace all the timing components at once, you will be good to go. As far as head flow they are subarus 3rd best flowing head, first being sti, second the rs-ra heads that are rare. I'm doing the swap on my legacy ej22t.

 

My suggestion, do it. The 2.5 has better driveability, more grunt, and around 40 more ponies than a 22. Reliability is the same. Period. And if you want to turbo it later, it's all cake and there's lots of guys on the rs forums with 300whp stock engine.