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Discussion Starter #1
anyone rebuilt their 2008 STI yet?

Thinking of cracking it open and making it a reliable base to start making more power.
 

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What do you need to know? Our pistons aren't forged, thats a good point ot start.
 

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What do you need to know? Our pistons aren't forged, thats a good point ot start.
I thought the JDM sti had forged pistions, but the USDM didn't...did that change?
Only the JDM 2.0L have forged pistons. No other versions do. I have USDM so mine aren't forged.I was just giving the guy an example of something he might ask for.
Sorry for the confusion. :p
 

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Just verified. SG gets the 2.5L so no forged pistons either. Sorry guys :'(
 

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The S-GT is basically a WRX spec car and a twin-scroll turbo results in it producing 247hp at 6,000rpm and 333Nm at 2,400rpm. 2.5-litre WRX (224hp and 306Nm)

The manual 2.5 WRX beats the 2.0 S-GT in the 0-100km/h sprint by two seconds with the S-GT coming in rather unimpressively, just under 8 seconds.


Bolted to the 2.0-liter turbo is the WRX’s familiar five-speed manual transmission with double-cone synchros in the first three gears. The shift action is a bit notchy, but the gears engage precisely.

From what we understand from our sources at Subaru, the same story will unfold for the U.S.-spec WRX fitted with a turbocharged 2.5-liter boxer-4 that comes from the U.S.-spec Legacy.

The 2008 Subaru Impreza WRX will generate around 224 hp and 226 lb-ft of torque, but more of that torque will arrive lower in the rpm range. A five-speed manual remains the standard transmission and a four-speed automatic is optional.

source:paultan.org/edmunds.com/


Wow that means S-GT gets equal length headers and the Dual AVCS is this true? Weird that the displacement makes the car that much slower though.
 

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Discussion Starter #8

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Generally speaking you will boost less than you could be if you go with higher comp, however, driveability tends to improve along with overall responsiveness. Depends on your goals. What are you looking to do? High-rev high-comp turbo? Not the way most people do it but I have seen this type of tune with great results not with peak power, but with tight courses where response and more N/As tend to specialize in. I know a couple people who run this way on rally also. This type of tune tends to put alot of stress on the motor, particularly the cylinder head and valvetrain.

Up to you and good luck.
 

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Discussion Starter #10
Generally speaking you will boost less than you could be if you go with higher comp, however, driveability tends to improve along with overall responsiveness. Depends on your goals. What are you looking to do? High-rev high-comp turbo? Not the way most people do it but I have seen this type of tune with great results not with peak power, but with tight courses where response and more N/As tend to specialize in. I know a couple people who run this way on rally also. This type of tune tends to put alot of stress on the motor, particularly the cylinder head and valvetrain.

Up to you and good luck.
Not looking for a high HP to brag about. Response and flat torque curve is what I am looking for. I'd take a big power band to high peak horse power any day.
 

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Think you answered your won question then ;)
Note that with forged internals you will still be quite a bit higher in terms of power than stock, and with the large powerband you were looking for. You wont be winning any dyno contests anytime soon though.

Have fun.
 

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Discussion Starter #12

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Think you answered your won question then ;)
Note that with forged internals you will still be quite a bit higher in terms of power than stock, and with the large powerband you were looking for. You wont be winning any dyno contests anytime soon though.

Have fun.
yup. did a baseline dyno 248Whp on a Dynojet
http://2008sti.blogspot.com/2008/05/really-300hp.html
You sooooo have to post that up on nasioc. They always complain about the big power losses
225whp for the new 08 saying the 04-07 is faster, Subaru overrated the 08 blah blah.
I told them the 08 had great tuning potential and was faster from the get go.
All those guys set me on fire even when I told them I owned an 04, then an 05, (didn't buy after because gearing changed) drove countless others in the 04-07 models. All I was doing was providing driver input.
I even tried telling them that octane numbers are too low here stateside, more flames.
"You damn noob blah blah" (All I did was change my forum name to a new one so my post count reset, been a member since 2006)
Then EVO guys flamed me more when I said the STi, (with me behind the wheel and with my drving style outdoes the MR by about a half second) DCCD rear, VCD off, even more when I adjusted the font camber of the STi to stock max. The MR didn't react the same when camber was adjusted, more electronics I guessed)
I am done ranting, they said alot more and I countered alot more but I quit that forum.
They're not even fan bois there, just a bunch of forum whores and haters.
I regret wasting alot of time providing posts there when all they looked at was post count and membership date to see if your post was informational.
 

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Yeah, I used to like nasioc alot more, but there are bunch of assholes there...

not everyone there has a superiority complex, but the people that tend to post the most just have a bad attitude.

I like it here alot, and I'd do alot before I let 3G turn into Nasioc#2.
 

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Discussion Starter #15
yup. did a baseline dyno 248Whp on a Dynojet
http://2008sti.blogspot.com/2008/05/really-300hp.html
[/quote]

You sooooo have to post that up on nasioc. They always complain about the big power losses
225whp for the new 08 saying the 04-07 is faster, Subaru overrated the 08 blah blah.
I told them the 08 had great tuning potential and was faster from the get go.
All those guys set me on fire even when I told them I owned an 04, then an 05, (didn't buy after because gearing changed) drove countless others in the 04-07 models. All I was doing was providing driver input.
I even tried telling them that octane numbers are too low here stateside, more flames.
"You damn noob blah blah" (All I did was change my forum name to a new one so my post count reset, been a member since 2006)
Then EVO guys flamed me more when I said the STi, (with me behind the wheel and with my drving style outdoes the MR by about a half second) DCCD rear, VCD off, even more when I adjusted the font camber of the STi to stock max. The MR didn't react the same when camber was adjusted, more electronics I guessed)
I am done ranting, they said alot more and I countered alot more but I quit that forum.
They're not even fan bois there, just a bunch of forum whores and haters.
I regret wasting alot of time providing posts there when all they looked at was post count and membership date to see if your post was informational.
[/quote]

For the sake of knowledge, I dynoed the same car on a DynaPack
http://2008sti.blogspot.com/2008/09/another-stock-dyno-crank-308ps.html
 

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I repeat my previous post LOL
;D
 

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Hello,

I'm from Australia.

Just wondering what the mechanical differences are between the MY08 2.5L Turbo WRX and MY08 2.5L Turbo STi? Referring to the ENGINE only.

Of course I note the following being different.

1) Turbocharger.
2) Intake Manifolds.
3) Exhausts.
4) ECU.

What I wonder is if the Pistons, Crank, Heads, Injectors are different?

I'm assessing the suitability to use the MY08 STi map as a basis for generation of a MY08 WRX map. I have the following baseline mods.

1) Walboro 255LPH Fuel Pump
2) OPENECU Flash Tune.
3) Greddy Profec Spec 2B EBC
4) 3" Turbo Back Exhaust

Will be adding a CAI, WBo2. No map changes thus far. Professionally tuned haltech installed tho.

Thanks
Matt
 

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Hi Matt from Australia! You have access to a wealth of knowledgeable tuners of the WRX in your country (AVO Turboworld, MRT Performance) although you may not be geographically close to them. MRT seems to really know their stuff...see their book "Subaru Performance Handbook". Have you tried contacting them with your questions? I'd be interested to know what they've done with the 08 WRX/STI. Also, Tomei Powered (http://www.tomei-p.co.jp/news/Report-EJ25-V1.html) has a really informative technical report on these engines.
 

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Hi Matt from Australia! You have access to a wealth of knowledgeable tuners of the WRX in your country (AVO Turboworld, MRT Performance) although you may not be geographically close to them. MRT seems to really know their stuff...see their book "Subaru Performance Handbook". Have you tried contacting them with your questions? I'd be interested to know what they've done with the 08 WRX/STI. Also, Tomei Powered (http://www.tomei-p.co.jp/news/Report-EJ25-V1.html) has a really informative technical report on these engines.
i like the tomei article. we should all read that article to learn about our engine.
 
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