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Old 01-30-2005, 05:06 AM   #1
calvin434
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Default STI 2.0L vs STI 2.5L - need help

I need your help and experiences so I hope to see lot of opinion here before spending lot of money. So thanks for your help....
I wish to upgrade my shortblock but dont know if I should buy 2,5L (USDM STI) shortblock or ver8 STI 2,0L with forget internals. here is what I want : 400 crank HP for fast street driving. Also something that will not stand only 10 000 miles and has to be rebuild when running 400 PS. I think that 2,5L block will hold this power much better with less problems just because its 2,5L and can make more torque.
please post here your opinion it will be great help - Its hard to find good opinions here in Europe. thanks
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Old 01-30-2005, 12:31 PM   #2
kpmatt00
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I like my JDM V8 STI motor, and for stregnth and performance, a USDM 2.5 cannot beat it. Plus you get dual scroll and higher revs, avcs, so much more. And 300 whp is totally duable. I am sure you'll be told to search, and there are TONS of posts out there, I know because when I upgraded I had a million questions. Good luck. Matt
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Old 01-30-2005, 01:04 PM   #3
STi-BOD-
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the usdm sti has forged internals cept pistons, and a v8 would be kick ass
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Old 01-30-2005, 01:12 PM   #4
Capt Crunch
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he's looking for a shortblock, not a longblock.

You can't go wrong with either, but I would get the 2.5 because the best part about JDM motors is the heads and cams. The 2.5 will hold the power you want to make.

Also, version 8 JDM blocks don't have forged pistons, only version 7 does, so keep that in mind.

Personally, I would buy a full JDM motor, but if you insist on just replacing the block, get the 2.5 because it will work just as well and you'll have more torque down low.
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Old 01-30-2005, 01:21 PM   #5
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the ver 7 has forged internals...I thought the ver 8 went to the hyp whatever cast pistons like the usdm sti...anyhow he is comparing blocks, not motors...so I would say EJ257
:edit: just read that Ben and I just wrote basically the same thing
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Old 01-30-2005, 01:25 PM   #6
XT6Wagon
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There is no reason to have a 2L anymore. Just get the EJ257 shortblock and call it a day.
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Old 01-30-2005, 01:56 PM   #7
pux888
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definately go w/ the 2.5, they will hold a ton of power w/ a good tune and the extra torque is awsome. ive been in v7's 8's and wouldnt trade my us sti for any of em.
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Old 01-30-2005, 05:19 PM   #8
john banks
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2.5 gives a very nice power band at about 380-400 BHP flywheel (Euro dynos) with a TD05H-20G turbo on 98 RON. This setup was giving me 1 bar at 2500 RPM, and virtually no lag for transients from 3000 RPM up. With STi valvetrain, although peaking at 5000 RPM if I ran a fair bit of boost, I could spin the engine to 7500 RPM and it gave a very flexible power band with no real lag, whereas the 400 BHP 2.0 I had was nothing like as responsive, although hampered by a 7000 RPM limit.

Your sensible rev limit will be 7000 RPM IMHO for either shortblock if keeping your WRX heads which will save you money. You'll get most out of the STi 2.0 with STi valvetrain allowing 8000 RPM.

I also think your OEM gear ratios are better suited to a 7000 RPM limit, a six speed with only 7000 RPM on a torquey EJ257 can feel frantic though, and your 5MT will not take the punishment indefinitely.

I think the 2.0 STi motor is stronger though, but at 400 BHP you should be OK with either, although bear in mind I've done headgaskets on UK fuel with additives at 450-500 BHP, as have others, and no one is certain on the reasons yet. It seems a lot of US cars only push hard on race gas because of its availability, and cost which is about the same as our 98 RON, which is about $7 a gallon?

Anyway, for flexible street use on twisty European roads I wouldn't go over 340 BHP on a 2.0 or 400 BHP on a 2.5 with a 7000 RPM limit. Response is lost, wear is increased, ground is not really covered quicker, octane demands increase.
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Old 01-30-2005, 05:59 PM   #9
calvin434
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john banks:
we have also 100 octane fuel here for 12 usd but 98 is 11 so i use 100 octane.

all:
thanks for help, I will wait for more opinions. which head gaskets should I buy with 2,L shortblock and stock 2,0L wrx heads to get the same(right) compresion?
thanks
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Old 01-31-2005, 08:10 AM   #10
calvin434
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anyone else?
thanks
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