Hoping for some answers... JDM EJ257 Specs

[Guitar_Guy]

So I bought a new wagon over the weekend, a stunning 2004 Forester STi in white and love it to bits!

But... After hours of forum searching and googling, I can't find any detailed specs or info about the engine. I've been lead to believe the JDM EJ257 has 280HP but can't find much else as all the threads are for USDM AND EUDM models.

My big questions are whether any of the internals are forged or semi forged? And is it an open deck or semi-closed deck block? These answers seem to be eluding me and would really like some info if anyone has any.

Any extra info that can be provided is also of interest, I've only owned Legacies prior to this so lots more to learn!

[CMPLSV]

I cant answer your questions... but have u signed up to OZFOZ? - you might find more forester specific info there?

[Johnnynz]

Not a Foz guy but when I was looking at buying one a little while back the Foz engine seemed to be comparable to the WRX of the same year. Might be a good place to start looking for specific specs.

I think they get the hypereutectic pistons around the era but don't quote me. Its the actual name for what people call "Semi forged".

[Kiwi_Fozze]

The forester engine is supposed to be the international spec 2.5, just a slightly more agressive tune because of the japan 100 octaine. I may be wrong, its been a while since i last researched. I Love the 04 foresters, good score...

[Guest]

Pretty much same same usdm/jdm. Im running a usdm one now. High silicon pistons not forged and semi block. Doesnt take much if you get det but if they dont det or have issues some have seen up to 500whp in states but 400hp with a gt35 seems to be obtainable on 98. Ill see how mine goes but i think heads are the issue after 300wkw. All from what ive read and what exp people have told me.

[syphe]

Should be about 265hp stock, Crawford in the UK managed to ring 240kw out of them with some mods as a drive away package, so should respond well to similar mods.

[Guitar_Guy]

Oops made a mistake, it's an EJ255... Not sure how different the 2 engines are, is it true that the last number only represents the turbo? Just what I've read so correct me if I am wrong.

[Guest]

Nope different but not much. Same piston compostion with diff dish and bigger bowl in head. 8.4 cr vs 8.2 in 257. Different head casting but same cams/springs unsure on valves but do have gen breakdown on file.

[EJ20T]

Yeah the spec is like halfway between a euro/aus wrx and sti engine