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Old 01-08-2003, 01:13 PM   #1
wrex03
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Default Engine questions for STI

Is the 2.5 liter boxer engine just an elarged 2.0 liter? Meaning all our goodies from the wrx will mate , or is it based upon the Rs engine And no goodie will transplant?

I'm sure this has been asked, but I didn't want to read through the couple hundred posts.

Thanks,


Dave
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Old 01-08-2003, 01:20 PM   #2
underground-mpyre
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Yea I read that too. EJ25 motor has a buttload of torque. I hope that if you modify it any, that the six speed will hold up. Yea the 6-sp, is built to last, than the wrx tranny, but I wonder what the torque rating is till it breaks. They should've kept the ej20 on it,(yes I know it is blasphemy) but probabley wouldn't kill the tranny. Even the wrc rally cars use ej20. check it out
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Old 01-08-2003, 01:23 PM   #3
mrbell
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The answer is a definitive "We don't know"

But most likely things will transplant. The WRX and the RS aren't even mutually exclusive. Many things will go between. Some things that, in all probability won't fit are pistons and camshafts. One thing that won't be easy, but possibly doable is are the heads. In all likelihood they will bolt together, but the AVCS won't work w/o some extra hardward...
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Old 01-08-2003, 07:03 PM   #4
ANZAC_1915
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The EJ22 and EJ25 have the same bore, I believe.

We are getting a block that (I presume) is a semi-closed deck version of it. (think 22B, although it was fully closed deck?)

The EJ20 and EJ22 have the same stroke, so we are getting the longer stroke EJ25 crank. Not sure if this is the new phase III motor or not. I would assume (hope) the crank is stronger than the current EJ253 crank.

The rods are probably specific to this motor too, as they've never combined the 2.5 crank in the higher spec engine.

I'm sure a bunch of people will decide that the engine needs a purple BOV, some kind of cold air intake kit to add what they think is 30 HP but in fact reduces the driveability.

Certainly more boost with appropriate fuel/air/timing changes will generate more smiles, but again I'd be surprised if this is possible (with absolute reliability) on even 94 AKI (without major changes like big FMIC etc).

Glenn
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Old 01-08-2003, 08:09 PM   #5
sperry
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Can someone elaborate on the differences between open, semi-closed, and closed decks? Or point me somewhere for the info?

--Scott
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Old 01-08-2003, 08:17 PM   #6
AKGC8
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Open:


Semi-Closed:


Closed:
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Old 01-09-2003, 12:28 PM   #7
sperry
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I think I get it... more reinforcement for the cylinder walls right? I see how that makes it a butt-load stronger...

But how's the cooling work on the closed deck!? Perhaps I'm not up on my boxer motor innards, but doesn't the coolant flow thru the space inbetween the cylinder wall and the rest of the block? If so, where's it flowing in the closed deck?

--Scott

BTW: great pics!
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Old 01-09-2003, 01:43 PM   #8
mrbell
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it flows thru those little passages... a little restriction in coolant flow doesn't really hurt anything... now if it were blocked, that'd be a problem... but I thought the 2.2L turbo had 97mm bore and the 2.5 is 99mm?
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Old 01-10-2003, 06:21 PM   #9
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anyone?
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Old 01-11-2003, 02:07 AM   #10
Jon [in CT]
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Quote:
Originally posted by mrbell
it flows thru those little passages... a little restriction in coolant flow doesn't really hurt anything... now if it were blocked, that'd be a problem... but I thought the 2.2L turbo had 97mm bore and the 2.5 is 99mm?
I've seen the 2.2 engine quoted as having either a 96.9 or a 97 mm bore. Regardless, I agree with you that the EJ22 bore is not the same as the EJ25, with its 99 mm bore.
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