15 replies to this topic

[Monkman08]

HI Guys,

 

I was hoping to get some advise on an engine swap from an 06 Impreza.

 

Old engine is EJ20. New engine is EJ25. Apparently i can use the EJ20 intake manifold on the EJ25 block but im not sure.. I would much rather to this than have to replace the loom/ecu

 

Any advice is appreciated.

 

- Steve

[Barbbachello]

Block has nothing to do with the intake manifold. If youre reusing the heads itll work just fine

[Monkman08]

Ok. The problem i have is a pretty long one. I cooked the ej20. Kinda. Blew the gaskets and the heads will probably need to be machined.

To replace the gaskets and machine the heads. the cost was close to 2.5k. The engine had just done over 200k. I thought it would be heaps easier. if i could get a newish engine. Some bad advice given to me. apparently you can't just swap an ej20 with an ej25 very simply. (Without changing the ECU and Loom). I managed to pickup an EJ25 with only 30k's on the clock. for $2000.

 

Ive heard from a subaru guru that just replacing the intake manifold should do the trick. I just don't know if the EJ20 manifold would fit on to the ej25 block. And i can't test fit it without voiding the new engine warranty/ ability to a refund. 

[Robert]

Manifold should just drop on

The only thing you need to be careful with is cam trigger wheels and things like that

I can't see any of that stuff being different

[Monkman08]

Manifold should just drop on

The only thing you need to be careful with is cam trigger wheels and things like that

I can't see any of that stuff being different

Without replacing or using the existing heads?

[Robert]

Using the 2.5 heads

[Monkman08]

Using the 2.5 heads

It sounds too good to be true haha. So many people reckon otherwise. The engines are basically the same apart from the bore size. Amiright? If you or know someone who has done this. i guess ill just risk not getting a refund on the engine. Id much rather the EJ25 over the EJ20. Thanks for your help BTW. much appreciated.  

[Barbbachello]

It sounds too good to be true haha. So many people reckon otherwise. The engines are basically the same apart from the bore size. Amiright?

Correct. You might run into issues with the ECU though. The earlier ECUS were able to handle this swap but im not so sure about a newer one

[Monkman08]

Correct. You might run into issues with the ECU though. The earlier ECUS were able to handle this swap but im not so sure about a newer one

Couldn't i just get an ej25 ECU from the wreckers if the one i have isn't self learning? 

[Barbbachello]

Couldn't i just get an ej25 ECU from the wreckers if the one i have isn't self learning? 

If the wiring is the same you could. Could have issues with immobilisers then

[Monkman08]

Technically speaking will the ej20 manifold fit the ej25? Without any modifications?

[Barbbachello]

Technically speaking will the ej20 manifold fit the ej25? Without any modifications?

most likely yes

[andrew_k]

To really know this will work you can use a site like opposedforces or partsouq to look up the crank angle sensor etc for your engine and for the donor car. Same part = ECU will be fine.

I have mild concerns about fueling. Are the injectors the same size for ej20 vs 25? They aren't in the turbo models. Therefore, will your ECU be able to provide enough fuel for the ej25 within its learning parameter boundaries, or will it be lean knock city? I don't know, but if want to know before all the effort of potting in a different motor.

What year and model is the ej25 from?

Was the 06 also available with an ej25? If it wasn't, you'll land yourself an $800 engineering bill before you can register the motor change with RTA.

[Badger1]

If all the parts are from the 06'-07' model range then all the ancillaries, heads, etc should bolt straight onto the 2.5lt block. Combustion chamber volume is smaller on the 2lt heads but not enough to be a problem. The 2.5lt ECU is mandatory and you must use what ever injectors that ECU was originally run with. The ECU need to be swapped by a Subaru service centre as they require re-coding. Other than that, it's a straight forward swap.

[Jimbo]

Probably would have been cheaper to just get the existing heads machined and thrown back in.

[Xamine]

Hey guys,

I've just acquired a 1996 Impreza. 

it is the EJ18 from the factory, but it now has an EJ25 in it.

it needs a blue slip and my question is, is this Legal under NSW road rules?