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Originally Posted by nKoan
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Originally Posted by MikeSTI
... I would think if I was going to get a new short block I would want a 2.5 or bigger 2.8 as a replacement rather then a 2.2, to me it sounds like closed deck is more important then the size it self?
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If you want ridiculous amounts of boost, yeah. Closed deck is more important then displacement.
I personally wouldn't do a 2.8 unless Subaru made it and made it was designed as a closed deck motor. If Subaru doesn't make it, I would assume that whatever 2.8 you want is a bored/stroked out EJ257 and it will actually be weaker then the EJ257 due to thinner cylinder walls. You can add more sleves and whatnot to strengthen the motor, but it still won't be as stong as a true closed deck motor. |
Oh, I forgot that part of Mike's post. 2.5 is as large as you want to take an EJ25 for high hp applications for several reasons.
There are two ways of increasing displacement- boring and stroking. There's not much more room for boring in either an EJ22 or EJ25- it's not really recommended to bore out more than what's required for an engine rebuild and remachining of the cylinder walls.
Stroking is safe, but doing it requires you to lower your redline at a faster rate than the displacement increases. A 2.8 liter EJ engine would have a redline of 5500 rpm, max. You lose your torque advantage by being forced to choose taller gears for your car. Frequently, you actually get a smaller powerband as a result of too much extra stroke.