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Discussion Starter #1
In my infinite boredom, I put the specs of the WRX and STi engines side by side to get an idea of how different the blocks/heads/other engine components might be.

WRX - 92 x 75 mm bore x stroke
STi - 99.5 x 79 mm

So this bitch isn't just bored, it isn't just stroked....it's just plain bigger.

It'll be interesting to see just how the blocks differ weight and size wise.

Reason I was wondering about this.....are the heads from the JDM STi the same as the USDM heads? If they made the blocks right, they'd be able to keep most of the rest of the parts the same, including the heads, plumbing.......and so on.

Anyone else have any other knowledge about this?
 

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How is it you conclude the motor is bigger from these numbers? Is it due to the bore and/or stroke being out of range for the EJ20?
 

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Discussion Starter #5
Depends what you mean by size. The displacement is obviously higher, but the bulk of my question is whether the block we will get will be similar to any other block used, whether it be the JDM STi, USDM WRX, JDM WRX.....all of the above and any not mentioned.

I don't know what the block of the EJ20 was like, let alone the bxs of that engine. It could be every WRX/STi engine ever made was the same block with different measurements cut out of it. That's what I'm wondering....
 

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I think you've asked the magic question: "what motor is the turboed 2.5?" I don't think we'll get a good answer till we see it for ourselves.
 

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Discussion Starter #7
I'd find it hard to believe it was simply the RS engine with a turbo. And I don't know enough about Subaru world wide to know if they have other 2.5 turbo engines anywhere.

I thought I heard somewhere this was an engine they've been working on for future use in other vehicles (Forester turbo?). It may be completely new.

But then you'd think a new block would mean new head ->new plumbing ->new intercooler(?) Just how much trouble would a completely new block cause. Because as far as I can tell, the USDM engine bay looks identical to the JDM engine bay.
 

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This is exactly why I said "we will not get a 2.5 liter for the STi".

Turns out I was wrong. :D

I'm not positive but I thought the RS's 2.5 is open deck while the STi's 2.5 is semi-closed deck so they either modified the 2.5 quite a bit or it's not it. It could be the Forester's turbo engine which I suspect it but it only makes 210 hp and 235 lbs of torque. If it is the Forester's 2.5 they did a lot to it.

I also noticed the engine compartments look the same which confuses me more.
 

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Discussion Starter #9
The way I meant the Forester engine was the other way around. Rumors are they are bringing a turbo Forester here, and the rumor guessed that engine would be the same engine used in the USDM STi, just detuned a little (minus AVCS, less boost, no forged internals).

That would make it a little more likely that they would do the R&D work for a completely new engine.
 

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Hmmmmm... crazy fast forester? If thats true it will become the ultimate yuppy moble. Sounds like fun. :eek:
 

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Yup.

http://vocuspr.vocus.com/vocuspr30/xsl/subaru/Profile.asp?Entity=PRAsset&EntityID=52927&XSL=PressRelease&Title=Releases

Incidentally, this site also lists the specs on that B11S concept, the first application of the rumored future twin-turbo H-6:

Thanks to twin-turbocharger, the engine will ensure a smooth ride in low- and middle-speed ranges while it achieves a maximum output of 294 kW (400 ps) and a maximum torque of 550 Nm (56.1 kgfm).
That's 394 hp and 406 lb-ft!!! :eek:
 

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Agent Chobos said:
Yup.

http://vocuspr.vocus.com/vocuspr30/xsl/subaru/Profile.asp?Entity=PRAsset&EntityID=52927&XSL=PressRelease&Title=Releases

Incidentally, this site also lists the specs on that B11S concept, the first application of the rumored future twin-turbo H-6:

Thanks to twin-turbocharger, the engine will ensure a smooth ride in low- and middle-speed ranges while it achieves a maximum output of 294 kW (400 ps) and a maximum torque of 550 Nm (56.1 kgfm).
That's 394 hp and 406 lb-ft!!! :eek:
I don't know. For some reason, I kinda wish they could get a bit more out of a TT h6. Something around 450 hp. Anyone else feel this way?
 

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Porsche's 911 TT makes what, 420 hp for the regular turbo and 450+ for the GT2? But that's with 3.6 liters. The Subie's still using 3.0. So I would say this engine is every bit on par with the 911's TT flat 6, which seems to be the benchmark for these sorts of things.
 

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This might be a stupid question, but what is the difference between a closed deck and semi-closed deck engine? Thanks
 

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I ran a search before I posted, I could not find anything, sorry.
 

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Thanks, that clears it up.
 
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