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Old 02-26-2003, 05:21 PM   #1
Rattles
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hi,

i have a deposit for the STI and i am no.1 at my dealer for a black STI. in the past week i have talked to a few tuners to see what are my options and to get some opinions on the new STI. out of 6 tuners (well known) 3 told me that they think that the 2.5 STI engine is GARBAGE. The other 3 told me that they think the STI engine would be great. i am trying to understand why am i getting mixed reviews on this engine. the way i see it the engine should be a great motor due to 2 reasons:
1) i doubt subaru will release a crappy motor on their flagship car.
2) by looking at the spec of the engine, it seems to be a great motor (semi-closed deck, forged everything etc...)

i am looking for your opinions and also some opinions from people with motor building background ( COBB, TURBOXS, MRT etc..)

thanks
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Old 02-26-2003, 06:02 PM   #2
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This has been covered:

http://forums.nasioc.com/forums/show...ngine+reliable
http://forums.nasioc.com/forums/show...ngine+reliable

Basically, those "tuners" probably have not actually seen/driven/touched the 2.5l STi engine. Some of them probably want you to import a JDM 2.0L EJ20 and associated parts so that they can make money in the process...something they won't be able to do with US dealer available 2.5l STi parts.

TRS
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Old 02-26-2003, 06:06 PM   #3
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thanks,
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Old 02-26-2003, 07:41 PM   #4
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I'll pass this on as a fact - they haven't touched the engine. They only know what it roughly will be like, but not a one has opened one up and fiddled with it.

Now, for my Opinion. The 2.5-litre turbo STi motor possibly won't hold as much boost as the 2.0-litre STi motors in Japan. But because of it's displacement advantage, it will more-than-likely produce more power than the 2.0 STi motor because it won't need as much boost to produce power. And it will produce more power everywhere, except in the high rpm's.

Cheers,

Paul Hansen
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Old 02-26-2003, 09:25 PM   #5
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thanks Paul,

thats what i think as far as power and boost goes, but some tuners are claiming that the motor will not hold on even with minor mods not to mantion big turbos and such
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Old 02-26-2003, 09:59 PM   #6
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well, maybe that's why they (SOA) decided to design the car in this way, so that there is a limit that people can modify the car. it seems like a win-win situation for them, if what some tuners claim holds true. SOA will not lose money if you break something, because knowing that it is capable to hold a hell of a load of power, they would know right away that you must've voided something, and i can assure that the warranty will be way more strict than that on the WRX. the other fishy thing about this "new motor", is the fact that why didn't the STi's in japan use this motor for their new model STi's, i know that 2.0L engines are good for race use, but it seems that they just thought about this for emissons purposes which is a bummer. also, they don't come with twin-scroll turbo like those in japan. i think it would be better to do a JDM STi 2.0L swap. looks like we got the semi-duff motor, still good though. i don't know though, it's just my speculation. i'm probably wrong.

Last edited by clamdip; 02-26-2003 at 10:07 PM.
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Old 02-26-2003, 10:51 PM   #7
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No, they didn't, and they wouldn't design the engine in this way.

Also, because of engine size tax laws, the vast majority of engines sold in Japan and Europe are 2.0-litres or smaller. In Japan, the vast majority of car sales are of 2.0-litre motors. Thus they don't want to lose those customers - end of story, as my tech editor would say.

Those tuners haven't even touched the engine, so how the hell would they be able to state that the motors cannot be tuned? Whatever those tuners are secretly hoping, this is not a NA RS 2.5 that's been converted to turbo duty - it's a brand new engine, folks. And it's been built up for power.

Cheers,

Paul Hansen
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Old 02-26-2003, 11:09 PM   #8
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Quote:
out of 6 tuners (well known) 3 told me that they think that the 2.5 STI engine is GARBAGE.
They're looking out for their own interests.

I don't know how much ultimate potential the engine has, but Subaru has clearly done more than throw a big turbo on the current 2.5.... this is a special motor built from the ground up with the US market in mind.

I would also say that in some ways it is a more specialized engine than the 22B. There are some internal construction features that have not yet been seen on any other Subaru engine.

My own personal position is that 300BHP is "adequate".

Glenn
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Old 02-26-2003, 11:17 PM   #9
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Orr there is always just waiting. I dont know it is getting tought as hell for me. I check about 4 STi message boards every 5 seconds.
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Old 02-27-2003, 12:39 AM   #10
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Quote:
I don't know how much ultimate potential the engine has, but Subaru has clearly done more than throw a big turbo on the current 2.5.... this is a special motor built from the ground up with the US market in mind.
Glenn -- Is it not an EJ-series motor then? I don't want to come off all high and mighty but I've been rebuilding Subaru EJ series engines for some time now. From old Legacy EJ20 Turbo blocks before there were even Imprezas up to the brand new STi and non-STi WRX motors. I'd really like to know how you think Subaru felt the need to re-engineer the entire design? And out of curiosity, how "Special" is a 22B engine..and be careful, I've rebuilt one before so I know what's inside. In fact, we've even supplied EJ25 parts for a 22B owner overseas...ahh, the horror!!

Quote:
And it will produce more power everywhere, except in the high rpm's.
shirokuma -- Are we going back to the old "big block vs small block chevy" argument here by saying EJ25's can't make power at high RPMs? Why not? It's not like they can't rev up there. If it's the Japanese tuners that are having problems then maybe they should stop trying to run EJ20 camshaft profiles and actually do some R&D to come up with a camshaft for the 2.5L so that they can actually make power at a higher RPM. It's definitely not due to the minor stroke and bore increase. I'm sorry but I just really wonder where you guys come up with this stuff sometimes...

I'm not trying to flame anyone, I just want to see someone put up some honest technical basis for their argument.

Cheers,
Trey Cobb.
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Old 02-27-2003, 01:12 AM   #11
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Relax, right now it's a known fact that the 2.5t in the USDM STi has a 7000rpm redline, and the JDM has a 7500rpm redline. Thus, if you ran both motors to redline in stock form, the JDM would make more power at 7001 - 7500rpm than the 2.5t - because the 2.5t has already hit redline. So yes, the 2.0 does indeed make more power higher up in the rev range than the 2.5t, simply because the 2.5t has hit it's limit at that point. As an owner of several turbo Subaru's, I've driven my B4's up to their 7800rpm cutoff quite often on the track, so I know that even 500rpm of difference at the top can make a difference to a few people. OTOH, those particular people don't need an explanation.

I made no mention about "built" engines, because I, and nobody else, knows what the 2.5t will be like after tuning. There are guesses, there are opinions, but there are no facts. And no matter how much experience you've had building these motors, until you've worked on this motor, you will be guessing or posting an opinion too. It may be correct, it may not.

The point Glenn, and I, are trying to reinforce is that this is not a RS 2.5-litre NA block. That is a fact. Whether or not STi adapted an existing design, or came up with a new design, the main point is that they did design it for turbocharging. Not just slapped a turbo on a old, NA 2.5-block that's just sitting around. I'm just trying to keep the story clear, pure and simple. There is a lot of misinformation floating around.

Cheers,

Paul Hansen
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Old 02-27-2003, 01:22 AM   #12
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trade offs are everywhere. If the EJ25 STI was a high reving highpower pump it will not be a low torquey and highly responsive pump. I beleive that for the North American Market Subaru choose B, torquey and responsive. The EJ25 block is semi closed with forged internals, that may be easy to predict but the heads are an entirely different story. BTW whichever tuner said it was garbage has never built an Engine. Because it will be just as garbage as anything out there now by subaru.

If we are talking about H6's then they might be right.
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Old 02-27-2003, 01:55 AM   #13
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Quote:
I'd really like to know how you think Subaru felt the need to re-engineer the entire design?
I don't think I said exactly that. But they paid attention to what was needed in the engineering of the engine for reliability and did it.

Quote:
And out of curiosity, how "Special" is a 22B engine..and be careful, I've rebuilt one before so I know what's inside.
That's what I'm getting at, the 2.5 STi engine has received a lot of engineering attention from Subaru. People seem to think of the 22B as being a street legal WRC car, when in a lot of respects it was "just" a 2 door STi IV with some detail changes and 2.2 liter engine.

Glenn
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Old 02-27-2003, 02:43 AM   #14
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could you go as far as to say that the 22B was so far one of the best cars built by STi and subaru yet? do you think the USDM STi will top it off and be the best car subaru and STi has made ever?
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Old 02-27-2003, 03:03 AM   #15
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Quote:
Originally posted by Trey
I don't want to come off all high and mighty but I've been rebuilding Subaru EJ series engines for some time now.
My research efforts have failed to find any association between Trey Cobb and Subaru engines prior to 2000. That would make it barely three years in the business of rebuilding Subie engines. Have I missed something?
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Old 02-27-2003, 03:05 AM   #16
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Quote:
Originally posted by clamdip
could you go as far as to say that the 22B was so far one of the best cars built by STi and subaru yet? do you think the USDM STi will top it off and be the best car subaru and STi has made ever?
Its possible, but the 22B has alot of die-hard type custom built stuff that makes it unique, not just the engine.
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Old 02-27-2003, 03:45 AM   #17
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It will be interesting to discover Subaru's nomenclature decision for the US STi's engine. For instance, the SVX's engine, even though it shared the same cylinder pitch with all prior and subsequent EJ2x engines, and the same bore and stroke as the EJ22, was finally designated the EG33 (question - why the G and not a J?).
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Old 02-27-2003, 10:53 AM   #18
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Its possible, but the 22B has alot of die-hard type custom built stuff that makes it unique, not just the engine.
Other than the fenders and paint, hardened RA gear set and red brake calipers, what else?
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Old 02-27-2003, 01:32 PM   #19
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keep it up guys, this is turning into a great info thread
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Old 02-27-2003, 02:18 PM   #20
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Jon [CT] - The EG33 was designated, at least through Fuji/Subaru technical papers, as the evolution or replacement for the older 6-cylinder models (ER27). Considering the time frame it was built, I'm not surprised they used a lot of the development they put into the EJ 4-cylinder series motors to develop the EG33. And technically Jon, if you want to split hairs its been since 1998 and I think we've probably built more EJ25's for turbo applications than anyone else -- definitely in America at the least. We also don't shy away from motorsports where engines are actually tested to their limits. 2002 Pro Rally championship and countless other SCCA and international race wins at least show we know a little about what we're doing.

Perhaps we just have some misunderstanding here because when you guys say "it's a completely new design" I'm think it's like a EA vs EJ vs EZ argument in which case those are all what I would consider "completely new designs" in the family of Subaru built boxer engines. However, simply putting forged pistons and utilizing the semi-closed casting method they've employed in other EJ-series blocks isn't what I would consider "completely new". Rather, built for the application. To think that the engine in the STi is simply a 2.5RS engine with a turbo slapped on is silly. However, like I've stated in other threads, I'd be very surprised if it's not simply a EJ25 case with the slightly modified semi-closed casting, stock EJ25 crank, WRX rods and special STi forged pistons and probably new ring set. And that's not to say the STi motor will be junk.... the thing I think so many people don't understand is HOW GOOD all the stock components are. All EJ engines already have FORGED high carbon crankshafts, forged rods, high-pressure die cast aluminum blocks, cast iron sleeves...I mean, they are awesome engines to begin with. There's really not that much left for STi to spend the time...and MONEY.. redesigning. "If it ain't broke, don't fix it".

Paul - Point taken regarding redlines. I just dislike blanket statements as I have to fight uphill battles with end-users and racers regarding their perceptions of the engines. Yes, in pure stock form the EJ20 may have to rely on revs more than the EJ25 to make a power figure. However, when given the ability to properly design components for an application, the EJ25 engines are more than capable of high RPM application.

Thanks for the discussion everyone. Its stuff like this that motivates me to spend the time to write up a nice technical article about Subaru engines. I have EG33s, a brand-new EZ30, and countless EJ series motors to show differences and evolutionary changes. We also have a STi on order so once it gets here, I'll probably pull the engine immediately just to take a peek inside. After all, it's all just speculation but based on what I've seen Subaru do by working on many different year model engines I would be surprised if it's radically different then what I think it is.

Cheers,
Trey Cobb.
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Old 02-27-2003, 02:20 PM   #21
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Quote:
the SVX's engine, even though it shared the same cylinder pitch with all prior and subsequent EJ2x engines, and the same bore and stroke as the EJ22, was finally designated the EG33 (question - why the G and not a J?).
Only engines with same cylinder count will share the same designation. All the EJ motors have the same Headbolt pattern as well as cylinder pitch. Remember the ER27 from the XT-6? Same situation as the EJ series.
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Old 02-27-2003, 02:30 PM   #22
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Quote:
Originally posted by Trey


And that's not to say the STi motor will be junk.... the thing I think so many people don't understand is HOW GOOD all the stock components are. All EJ engines already have FORGED high carbon crankshafts, forged rods, high-pressure die cast aluminum blocks, cast iron sleeves...I mean, they are awesome engines to begin with. There's really not that much left for STi to spend the time...and MONEY.. redesigning. "If it ain't broke, don't fix it".

[/b]
Trey- do all the 2002 US WRX engines come with these components as stated above? wow, that's new information for me, i really didn't know that. so in terms of reliability, how much could the stock block handle in terms of engine power and stress? so basically, just the pistons aren't forged, so a stroker kit would be very nice for this engine, right? thanks for the information, very very useful. i guess the stock block isn't that bad afterall, however, the tranny is the main problem, right!
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Old 02-27-2003, 04:43 PM   #23
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Trey- The WRX has an EJ20 and ahas CAST rods not forged like that of the STI, so the STI won't use standard WRX rods,

also IIRC the EJ25 comes with the forged crankshaft, (not sure about the US WRX though).

If anyone has the time to look up these specs to see what is really under the hood of the US WRX please post it.
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Old 02-27-2003, 05:23 PM   #24
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great info!!

i totally agree with Trey on this one. if worst comes to worst i will just pull out the engine and buy a built 2.5 from Trey
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Old 02-27-2003, 07:34 PM   #25
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Quote:
Originally posted by Trey
However, like I've stated in other threads, I'd be very surprised if it's not simply a EJ25 case with the slightly modified semi-closed casting, stock EJ25 crank, WRX rods and special STi forged pistons and probably new ring set.
What I've heard from somebody that's seen the internals leads to me believe that it's actually a bit more than that. However, I'm not the biggest of engine guys, so my impression of what he said might differ from yours.

Cheers,

Paul Hansen
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