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Discussion Starter · #1 · (Edited)
Hi all,

I need to hear the truth from the people on this forum and STI owners. I've either been watching too many STI videos on you tube in particular (Josh Bader - Bader Built) and been brainwashed or the workshops in Sydney Australia are being conservative or have done tests and results vastly differ from Baders builds.

What I really want to know is can you really get 700hp out of a standard unopened EJ25? I mean I have watched and seen it happen with my own eyes with Josh's White STI. I understand reliability is an issue but if he can do several 10 sec passes before he melts the piston you would assume running a tamed 400-500hp would be considered safe and OK for a daily?

In Sydney the Subaru workshops will only tune your factory un-opened EJ25 on E85 to a max 260-270awkw. I have asked all the workshops about 5 and they all say that the 260-270kw is the max that they will not tune the car to have more. And then we watch BaderBuilt and say WTF!

So which one is it? Do we have people in Australia running more than that on a standard motor? Is there anyone else with more than this overseas? If so how is the motor travelling?

Im a factory trained Subaru Master Tech and I own a 2020 STI currently running 200kw package which includes

  • IAG AOS
  • PROCESS WEST TMIC
  • DW 340 FUEL PUMP
  • 3 PORT BOOST CONTROLLER
  • COBB ACCESSPORT
  • COBB BIG SF INTAKE
Running on Unleaded 98

In order to get the 260-270 it is recommended I run the following

  • Blouch 2.5XTR 8cm rear housing
  • ID 1050x injectors
  • Zeitronix Flex fuel Kit
  • Radium FPR
  • PSR Silicon Intake
  • PSR Headers and up pipe
  • Air pump delete plates
Look forward to the response and advise!
 

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As we've seen, it can be done, but for how long? I think those tuners in your area are smart by not pushing too much out of a stock block. There's a few I've seen running high 300WHP STI's on a stock block, but 400-500 WHP would be a ticking time bomb in my opinion.
 

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can it be done, absolutely, will it last, unlikely. yeah, you could probably make 450-500whp from a stock block, and it may last a minute, an hour, or a year, but eventually, it'll go boom. back before the type RA block showed up, the general consensus was that anything right at or higher than about 375whp, was basically a ticking time bomb. with the type RA that seems to be shifting to being able to make right in the 400whp range for extended periods of time on e85, and while it might be possible, most tuners dont want to push that, because if they have a few years experience they will know that it may blow up, just like the pre type RA blocks would. and generally speaking, most people incorrectly blame the tuner for ANYTHING. even if it's not tune related. one of my best friends is a tuner and you'd be shocked how many customers with "alot of knowledge" come back to him asking him to fix something that is 100% unrelated to the tune.

your best bet, save money for an IAG shortblock, tune your car in the 350ish whp range and enjoy it, and when it's built, then turn it up.

DO NOT GET POWER HUNGRY, just look at the piston i destroyed in my build thread on here to see why.
 

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I agree with you both. Ideally it would be great to hear from owners who have the 350whp and how long they have had their stock motors in-tact
Mine lasted about 8 months at 343whp (06 STi stock block) it blew when I got race fuel+high boost and power hungry. It may or may not have lasted longer at that 343whp. I’d guess at minimum another year. Maybe longer (I did beat the car pretty hard a lot)
 

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My personal limit is that full bolt-on with a stock turbo is the limit for an OEM block.
RA block (2019+) can handle a mild 20g sized turbo but not one turned up all the way.
By handle I mean be a sorted car that isn't at risk of popping at any moment.
I'm there right now making 282whp/325wtq on 94oct.
Those setups vary drastically on power depending on if you're running gas or e85, but thats the line I draw on the hardware component.

If you desire to run a bigger turbo I wouldn't bother installing that on the stock block and just go ahead and order a forged shortblock.
That way you don't blow something up and trash the heads too and have to buy a longblock, which will cost you more money in the not so distant long run.
Then you can just go ahead and get a bigger turbo and shoot for power in the low 4's.
 

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I agree with you both. Ideally it would be great to hear from owners who have the 350whp and how long they have had their stock motors in-tact
my 2011 STi made 350 whp/400 wtq on full bolt on (EL headers, EWG) stock turbo E85 for 8 years of the 10 years I owned it. When I sold it, it was still running strong @ 90k miles. I had almost no issues with the car but I knew it could go boom at any time, so always planned a block replacement.

I picked up a 2020 STi but just sitting at stage 1 protune right now.
 

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I agree with you both. Ideally it would be great to hear from owners who have the 350whp and how long they have had their stock motors in-tact
the numbers I had (343whp/364wtq iirc) were corrected numbers. I believe uncorrected i made right at 350. like i said, the car lasted just fine until i got power hungry. when i got power hungry, i got race gas, pushed 25psi, and based on the logs was probably in the 400whp ish range. that's what blew the motor.
 

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If you want to push the stock block, and no tuner will do it for you, you could try getting an e-tune. I know a few etuners who will send it to the moon if that's what you really want. I have a 2021 STI with a Cobb intake and 3 port ebcs making 319whp and 357wtq from Ambot Tuned. With the setup you want to run, I think you could easily make 380-400whp (maybe 420 on a good day) and 450-70hp or so on E. My instinct is to tell you not to, but the new RA block seems to be holding up pretty decently to higher power levels (500hp or so). If you really want to send the stock block, go for it but definitely have another block lined up. You can also take the stock block and throw some rods, pistons, and clearances in and probably be fine that way too. At least you won't be buying a whole new block if yours blows up. The only issue with getting an e-tune is that you will probably have to stand my Cobb's Greenspeed compliance (no good ways for E and no emissions delete of any kinds). If you end up finding someone to tune your car, I would also recommend tgv and egr deletes to go along with your secondary air pump delete. The new pistons are made out of Aluminum silicate using a hypereutectic casting process that makes them significantly stronger, but more brittle when exposed to heat. So make as many modifications as you can to decrease heat near those pistons. (Extra fuel, front mount intercooler, bigger turbo lower boost, etc.) Many of the strongest factory engines such as the 2jz-gte, k24, 4g63, all use Aluminum silicate as their primary piston material. I wish you good luck on your "how much abuse can my stock block take" journey.
 

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Aussie here, one thing to note is that american dyno numbers are not direcly comparable to the numbers we have over here. Most Australian tuners have a Dyno Dynamics or Mainline dyno which are locally supplied. In most cases once you convert from kW to hp things will still fall short of the american hp figures by 10% or more.

You are right in saying that you don't see many EJ257s here pushed above 280kw at the wheels, and we missed out on the Type RA strengthened pistons so that doesn't help.

At this power level it all comes down to your usage. With heavy track use i don't envision it lasting very long, especially without any cooling improvements. If it's a street car that sees some motorkhana, spirited driving, and occasional drag runs, it should last with strict maintenance, but you are still rolling the dice.

My engine lasted about 3 years before it went at 200kw, it saw a fair bit of track use
 

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Discussion Starter · #13 ·
Aussie here, one thing to note is that american dyno numbers are not direcly comparable to the numbers we have over here. Most Australian tuners have a Dyno Dynamics or Mainline dyno which are locally supplied. In most cases once you convert from kW to hp things will still fall short of the american hp figures by 10% or more.

You are right in saying that you don't see many EJ257s here pushed above 280kw at the wheels, and we missed out on the Type RA strengthened pistons so that doesn't help.

At this power level it all comes down to your usage. With heavy track use i don't envision it lasting very long, especially without any cooling improvements. If it's a street car that sees some motorkhana, spirited driving, and occasional drag runs, it should last with strict maintenance, but you are still rolling the dice.

My engine lasted about 3 years before it went at 200kw, it saw a fair bit of track use
What year model car and how many KMS?
 

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Discussion Starter · #15 ·
Thanks for the info guys.

I now have another question. I have bought the 2.5XTR (with 3cm inlet and T51r mod) + supporting mods to flex tune my 2020 STI on e85. Ill be running 38mm EWG aiming for the 270kw. I spoke to a different tuner and he was surprised as to why I went with the 2.5 and not the 1.5XTR. I explained that eventually I will do the bottom end and this turbo (2.5xtr) will take me over the 300kw with no issue and thats when he also mentioned that the 1.5xtr would also get me to 300kw whenever that happens.

My understanding is that the 1.5xtr has a 56mm compressor vs 60mm in the 2.5xtr. Im assuming full boost on a 1.5XTR is at 3,600 vs 4,200 on 2.5xtr. I currently have the 2.5xtr in the box unopened and im able to swap for the 1.5 if I want. Just struggleing to get the right answer.

Also I was told by one tuner that i could not fit the blouch turbo without removing and carrying out the air pump delete. As the air pump delete metal lines that sit on the block in the valley will interfere with the turbo and not go on. The other tuner tells me that I do not need to remove and carry out the air pump delete. Other than the pump working on cold start I see no reason why it would need to be removed or is there other performance gains.

Can somebody clarify the above please?
 

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Correct, I'm on a 1.5XTR 8cm, 301kw atw on flex fuel. Full torque (not boost) comes at around 4500rpm.

With a 2.5XTR 8cm you'll see 320kw atw. You could probably make 320 on a 1.5XTR 10cm though

Definitely recommend an air pump delete just for engine bay space and simplicity. The block off plates are $80 and you save a tiny bit of weight chucking out the air pump. You'll need a tune to remove the check engine light.

Your 3cm inlet may be a pain in the ass to fit but the mechanic should take care of it hopefully. Definitely recommend phenolic spacers for the intake manifold to gain a bit more clearance to fit the larger turbo inlet hose
 

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Discussion Starter · #17 ·
Correct, I'm on a 1.5XTR 8cm, 301kw atw on flex fuel. Full torque (not boost) comes at around 4500rpm.

With a 2.5XTR 8cm you'll see 320kw atw. You could probably make 320 on a 1.5XTR 10cm though

Definitely recommend an air pump delete just for engine bay space and simplicity. The block off plates are $80 and you save a tiny bit of weight chucking out the air pump. You'll need a tune to remove the check engine light.

Your 3cm inlet may be a pain in the ass to fit but the mechanic should take care of it hopefully. Definitely recommend phenolic spacers for the intake manifold to gain a bit more clearance to fit the larger turbo inlet hose
will the 3inch inlet fit without the spacers? Im doing the work at home as Im a mechanic by trade
 

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will the 3inch inlet fit without the spacers? Im doing the work at home as Im a mechanic by trade
ok so i'm only quoting this but trying to address all the points you commented.

1 - the 2.5 is a bigger turbo, yes, but according to the google, 300kw aka your stated goal, would be 402whp. i'm not sure how the dynos over there vary, but for my area we use dynojet+sae correction+5 smoothing. with that factored in, a blouch 20g xtr will get you to that point if using e85/flex. the 20g xtr and the dom 1.5xtr are my two favorite stock location turbos for subaru. the 1.5 spools slightly slower, but is hardly noticeable on the street. I have driven in quite a few different setups, and these two really are my favorites. with the dom 1.5 xtr, on pump gas we'd regularly see 390whp (290kw) and on ethanol we'd typically see in the 440whp-450whp range (328kw-335kw). Keep in mind, different dyno's will read differently, and the same car with the same tune and such can make vastly different numbers on different dyno's, so take all this with a grain of salt. that said, the 1.5xtr with 10cm hotside and 3' inlet would be my personal vote for your stated goals. just because it will spool faster than the 2.5xtr. the 2.5 xtr is a quality turbo too, and will be fun.

2 - the 1.5xtr probably wont hit full boost at 3600rpm in 4th, maybe more like 3800, granted, what full boost is will cause this to vary. and the 2.5 will likely be in the 300-500rpm slower spool. still either will be fun.

3 - you should be able to fit any of the blouch turbos without doing the air pump delete, that said, if you can do the air pump delete and have it tuned, do it. it'll save about 20lbs, and make less clutter in an already cluttered engine bay. it's one less thing that can fail, and does almost nothing for emissions. aside from weight, you wont really get any performance gain so to speak, just what i stated for benefits.

4 - the 3' inlet will fit without spacers, however it is a VERY tight fit. and honestly kinda a pain to get in there. spacers for the manifold are pretty cheap, it'll still be tight, but it will make life slightly easier

5 - just something to consider, if you are going through cobb, flex fuel/emissions deleted items are no longer supported via their accesstuner. meaning if you are using cobb, you wont be able to do flex fuel, it would have to be straight e85 (you could get an ethanol sensor and do what was done before flex fuel, have like 6 tunes, and put one on based on the current ethanol content). you would not be able to run tgv/air pump/cat deletes without a CEL. Opensource and standalones still allow this to happen (hp tuners might too, not sure on that). but it's something to think about. even if your country doesnt care, cobb across the board did this because it's a US based company and has to deal with our epa. it's frustrating i know. if you arent going through cobb, basically everything i just said is null lol. just wanted to let ya know if you were using their tuning software+accessport.


if you have any other questions let us know, or if i need to clarify anything. i have worked at a performance shop specializing in subaru, and have ridden in and/or driven many many turbo setups. and i personally own a 20g.
 

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Discussion Starter · #20 · (Edited)
3 - you should be able to fit any of the blouch turbos without doing the air pump delete, that said, if you can do the air pump delete and have it tuned, do it. it'll save about 20lbs, and make less clutter in an already cluttered engine bay. it's one less thing that can fail, and does almost nothing for emissions. aside from weight, you wont really get any performance gain so to speak, just what i stated for benefits.
Very interesting that you say this. At times in Australia police can pull you over and pop the bonnet to inspect the car for modifications. One of the instant fails is a blow of valve. That's enough to defect you and potentially send you through the pits (EPA) inspection. Even if I did the air pump delete I would leave the hardware there so the engine looks somewhat "standard". The only reason I was to do this mod was because the tuner said it was necessary to fit the Blouch 2.5xtr. turbo wouldn't fit otherwise. It even is recommended by blouch to do along with tgv deletes? This is why I'm asking this forum do I or don't I need to do this. As you stated no other benefits or performance gains so for me I'd prefer to leave it. So interesting to hear that you said I don't need to removed the pipes particularly the passenger side pipe that runs in the valley and down near the turbo up pipe.

5 - just something to consider, if you are going through cobb, flex fuel/emissions deleted items are no longer supported via their accesstuner. meaning if you are using cobb, you wont be able to do flex fuel, it would have to be straight e85 (you could get an ethanol sensor and do what was done before flex fuel, have like 6 tunes, and put one on based on the current ethanol content). you would not be able to run tgv/air pump/cat deletes without a CEL. Opensource and standalones still allow this to happen (hp tuners might too, not sure on that). but it's something to think about. even if your country doesnt care, cobb across the board did this because it's a US based company and has to deal with our epa. it's frustrating i know. if you arent going through cobb, basically everything i just said is null lol. just wanted to let ya know if you were using their tuning software+accessport
Lucky for us here in Australia we didn't get the affects of project green. We have full Cobb functionality with no restrictions. YET.
 
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