Engine swap JDM EJ25 STI engine
 

I am thinking this engine could fit in with the stock mounts. I havent found much information. I think its a good topic to be discussed and wont be too expensive to do if you find a good used engine supplied with the turbo.

Mr Gushi has a similar ej25 engine in his car. It would be nice if we could narrow down year and perhaps part numbers. In case someone wants to order from Japan.

Ken Gushi and Toshiki Yoshioka both use EJs. Only seen pics of Gushi's and all I could notice was the cosworth intake manifold. Yoshioka uses a tomei genesis.

Its not impossible by any means but those guys have race team budgets. If you have money then ok.

There is also the debate that the FA is a better engine. I'm going to wager this thread will turn into an argument about that, the last one did lol.

Edit: I think the mounts are a tad different anyway

I guess you are right the FA is a newer engine after all but its only a 2lt.

displacement isnt everything

There's no replacement for displacement. Except Forced Indiction. N/A vs. N/A? Never a replacement.

Oh so his putting an ej25 and going na with it ? :w00t:

This isnt some small block vs big block debate, but with alot of import motors displacement isn't everything.

:popcorn:

The FA engine is stronger and apparently makes more power than the EJ engine. Crawford did a test, same size turbo, on both the EJ and FA engine. The EJ engine made 360 horsepower and the FA engine made 430 horsepower - same turbo, smaller engine... hmmm - you might just want to stick with what you got :D

would assume extra displacement would make a significant power gain. Ken and Yoshioka both have 2.5lt engines no? I wish there was an in-debt write up about jdm engine swaps.

If you could find a great deal on a used engine. In theory it would cost just about the same as going with a premium turbo kit.

I am sorry for opening a can of worms, I m just trying to weight my options and learn more.

Perhaps I should give up engine swap and go with a turbo kit but i wont be the same. Anyways that engine would be awesome on gt86 platform.


http://www.importtuner.com/features/.../photo_12.html

If you have the money to do an engine swap, plus replace parts and deal with all of the unknowns with regard to fitment and placement - go right ahead - but at the same time it seems to be more trouble than its worth. Do you want to go through that whole process? What are you looking to benefit/gain from a swap vs. a FI kit? Just horsepower?

I could not afford a new crate engine at this time, but if I could if I find a used engine. It would be pretty cool to have a 2.5 sti engine that is mostly all that got me fired up I guess.

I was thinking about sc and turbo charging at the same time. but thats going to be way too expensive. Similar to MRT Performance FR-S.

Bottom line. I should just go with a turbo kit like greddy, save my money and dont complicate things. All I need is some more power at the top end for occasional track use and call it a day.

I'm no expert, but I'm certain that the 12.5:1 compression ratio compared to the 8.5:1 in the EJ is to blame for the extra bump in power. Find an EJ25 at 12.5:1 and im sure you'll see more power in that engine than the FA20

If an EJ had a 12.5:1 CR, then you'd see powers well above that 430hp you mentioned.. Remember, even though less displacement, compression matters when going FI

Well I don't know this for sure but current STI's run like 15-20 psi right? If that is the case, I don'y think that you could run that high of psi @ 12.5:1 on the EJ. I might be wrong on that though...


That would be an interesting test, however, I don't know this but what is the difference when you look at

[2.5L @ 12.5:1] vs. [2.0L @ 12.5:1]
and
[2.5L @ 8:1] vs [2.0L @ 9:1]

same turbo

Not every block is built to withstand 12.5:1, and DI helps a lot with high cr ;), Ferrari now has a 14:1 engine that runs on pump


Sent from my IBrick

That was my assumption when Crawford described their (vague) test results with their brz. EJ runs at its cr because that is where it is optimal - likewise with the FA - it has a high cr because that is where it is arguably optimal.

More torque and no direct injection... Sounds like a winner to me.

So first of all the JDM STi doesn't use a 2.5L engine, it still uses the EJ207 2.0L engine it always has.

Second if you ran the EJ257 at 12.5:1 CR on anything but E85 or low boost it would detonate itself to death in about 15 minutes. It has a hard time not detonating at 8.5:1. DI goes a long way...

The FA20 is superior to the EJ257 in pretty much every way. The only reason those guys used the engine is because they were known setups which were in previous cars. There is no way I would put one in my car. You don't think Subaru has made any advancements in engines since they came out with the EJ257 in 2003?

No, you won't.

There's no replacement for displacement. Except Forced Induction. N/A vs. N/A? Never a replacement.
C'mon man! Reads whats I's wrotes!:cheers:

I did and hence I said it's not a small block vs big block debate.


Sent from my IBrick

Couldn't be more wrong.

Explain =) Compression and or tuning may play a small role. But consider:
Honda:
3.2L v-6 ~ J32A1 225hp
3.5L v-6 ~ J35Z2 272hp

Basically the same drivetrain, just a higher displacement. Even the compression ratio's are close.:lol:

:dnftt: lol

You can literally take the same EXACT motor, change the runner length on the header and make more power.

Same thing could be said of changing exhaust port sizing for torque, etc.

It is NEVER just displacement.

Have you ever heard of variable valve timing? What about cams? what about piston speeds? What about number of cylinders with same displacement?

You clearly hadn't thought this through.

Also, for those that want to get rid of DI..

There's a reason Audi, BMW, Merc and now virtually every other car manufacturer are going that route. Consider for the last decade that they have had pretty much flat torque curves (and gobs of it too) on shitty pump gas on tiny 4 cyl turbo applications. That doesn't happen without DI. DI does not only atomize the fuel better, it cools piston heads and the combustion chamber immensely. There's no way Subaru would have even considered running a 12.5 CR on shitty pump gas if it weren't for DI. Just because you guys can't figure it out, doesn't make it bad.



Edit: OP, if you want to throw boost at your car, change the pistons to a slightly lower CR like 10:1. Stock rods should be plenty enough for you unless you are going to be beating on her like she owed you money. Our rods are the same that go into the FA20DIT that will be in the new WRX as well as already in the Forester. If they are good enough for 295/295 factory, I'm sure they will be just fine for a little more than that.

:sigh: