[Kevin M]

Originally Posted by MikeK

Actually Mike I do agree with you, I think the 4G63 engine is way better than the EJ205/07/57. And I agree that if they had come with forged internals, then detuned for emissions, you could push the car further with aftermarket parts. But no car manufacturer is going to spend extra money that they don't have to.

A lot of guys on nasioc are having luck pushing the EJ257 to 400+whp just adding forged pistons. Most of the 400 whp STis that have the stock pistons seem to be breaking after a while. Also, 91 craptane is a serious limitation, I am not convinced that a safe 400whp is possible at all on a small engine on 91.

I was talking with Nate last friday, and I asked him how far you can push one of those built blocks (you know, with the forged crankshaft/rods/pistons etc) ... I asked how much you could safely boost and his exact words were "you can boost until the cows come home". I am not sure what that is in psi, but I am guessing it is pretty high. He also said that a built engine in an STi could easily make 450 - 500 hp at the wheels :shock:

I guess like most problems in life, it can be solved by throwing vast sums of money at it

the Evo motor does have some advantages over the EJ series, especially once you start reaching for major power levels. In a stret car, in the 300 whp area, the EJ25 actually has advantages, namely low end torque.

Another thing I glossed over in that long post is octane- remember that all production engines have to work at the lowest common denominor; that means you have to be able to avoid knock on the worst gas in the worst conditions with the highest engine loads, without breaking. Ever. That really puts a damper on peak power you can make.

Also, both of yo have used the term "detuning"; that's really not something that exists. If I took a stock STi and tried to make 250 crank horsepower with it, it would run like ass, and be less reliable than it is stock. Not to mention, it would probably not run as clean. You simply can't take a high-octane JDM motor, and retune it on our 91 and expect it to run strong OR clean. You're asking it to do things it's not built to do.

Okay, I am running long again. I'm goin to start working on a series of posts for the tech archive. Hopefully it will be comprehensive enough that I can simply refer to it in the future.

P.S.- all Phase II EJ25 cranks are forged- even in the RS.