The Truth Behind The Subaru EJ-Series Engines -

[Aaron 2NR]

a lot of relevant information in this post

http://www.clubwrx.net/forums/engine-mo ... guide.html

[JJ16]

the thread is about stock engines' strength or forged engine build/tune?

the points you all bringing out on forged engine/build/tune exist with all platforms...

I would believe the point of the thread is "the truth behind the Subaru EJ-Series Engines-


they remain EJ Series engine be it forged or not... Stock STi motors are forged....

[kjaglal76v2]

not sure if subaru or honda ched

[Ted_v2]

Not sure if everybody does only bawl. Retune Retune.
Something tells me if subaru ecu wasn't flashable. Subaru would have a better rep in Trinidad.

If people go chook and dig up it must spoil.

[kjaglal76v2]

Not sure if everybody does only bawl. Retune Retune.
Something tells me if subaru ecu wasn't flashable. Subaru would have a better rep in Trinidad.

If people go chook and dig up it must spoil.

huh? evos flashable; reputation intact

[16 cycles]

they remain EJ Series engine be it forged or not... Stock STi motors are forged....

Any references for above?

Always thought they came with hypereutetic(sp) pistons.

02 was semi closed deck and 03 onwards were open deck /jdm

[nervewrecker]

Not sure if everybody does only bawl. Retune Retune.
Something tells me if subaru ecu wasn't flashable. Subaru would have a better rep in Trinidad.

If people go chook and dig up it must spoil.

Aren't there aftermarket ECU's?

[Aaron 2NR]

Stock ecu is flashablel

The issue with management is getting the avcs to activate that's why aem discontinued the management for the jdm 06 up

[Lance]

they remain EJ Series engine be it forged or not... Stock STi motors are forged....

Any references for above?

Always thought they came with hypereutetic(sp) pistons.

02 was semi closed deck and 03 onwards were open deck /jdm

I've never seen any official correspondence that said STi Engines have forged intervals. Online hearsay has peddled the notion that the V7 motor had some sort of forged piston. But again I haven't seen any valid source of this. Perhaps JJ can share the source.

All 01+ STi's were semi closed blocks.

[R. Mutt]

I was referring to kjaglal76v2 comment about Subaru's catching up. In this particular case, it's a stock motor so most of the issues related to "mechs" or "rebuilding" are irrelevant. This is a tuner dependent scenario.

I'll also touch on your other comments as they are also somewhat erroneous

Minimal slap on STARTUP on a rebuilt motor with forged pistons is totally normal. Actually If there isn't a slight amount of slap on STARTUP then I would be worried.

The reason is simple, forged pistons are not cast OEM pistons and they will expand more with heat. If the piston to bore clearance doesn't account for this then the clearance will be too tight after expansion.

In any event, this is not squarely the mechanic's fault as there are a lot of other players involved. Machine shops locally do not rebore with torque plates so cone-ing is expected post heads assembly. At the end of the day, if i'm a tuner and I hear excessive piston slap on a warm engine then I will refrain from tuning. Can't they tell the difference? This is not to nullify mechanic fault but there is a certain chain of responsibility that should help mitigate this problem.

Going over 300 (320+) on stock 550cc injectors without methanol injection is pushing the IDCs to the limit, no tuner will dispute this. Any that say the IDCs are safe is probably running a lot more timing than they should. 1000cc is overkill but telling a customer that pinks are OK is playing dice with your motor.

I'm glad you are in this thread, you say exactly what I'm thinking a lot of the time...saves me from typing.

[mitsu]

they remain EJ Series engine be it forged or not... Stock STi motors are forged....

Any references for above?

Always thought they came with hypereutetic(sp) pistons.

02 was semi closed deck and 03 onwards were open deck /jdm

I've never seen any official correspondence that said STi Engines have forged intervals. Online hearsay has peddled the notion that the V7 motor had some sort of forged piston. But again I haven't seen any valid source of this. Perhaps JJ can share the source.

All 01+ STi's were semi closed blocks.

Found this clip sometime ago about the v7 having forged pistons.MRT is ah boss in the subie world
https://www.youtube.com/watch?v=

[JJ16]

they remain EJ Series engine be it forged or not... Stock STi motors are forged....

Any references for above?

Always thought they came with hypereutetic(sp) pistons.

02 was semi closed deck and 03 onwards were open deck /jdm

I've never seen any official correspondence that said STi Engines have forged intervals. Online hearsay has peddled the notion that the V7 motor had some sort of forged piston. But again I haven't seen any valid source of this. Perhaps JJ can share the source.

All 01+ STi's were semi closed blocks.

Found this clip sometime ago about the v7 having forged pistons.MRT is ah boss in the subie world
https://www.youtube.com/watch?v=

Thanks much Mitsu ....

Im rather shocked that lance doesnt know that... i am no "bird" or "garage 61" but i do everything on my car myself, which would have initially comprised of much research and reading...

I'm sure lance does the same??

[Lance]

If you look at my comment you would see that I said exactly the same thing that Bret said, before the video was posted. So I am very much aware of what the claims are.

I stand by my view that it is unsubstantiated. Does that make it false? No it doesn't.

Moreso, the comment that Bret is making in the video is very different to the claim that you made in your post. He is referring specifically to the v7 (bugeye) Sti, whereas you are making a comment across STis in general. I urge you to be more focused on your comments.

[JJ16]

^^ thats based on your interpretation of language sir lance... if i meant in general i would have said

"All STi motors are forged"


See the part where i said "be it forged or not .... Stock STi motors are forged "

I could have said ALL STi motors are forged, and that was not said..

...but lance i've long noticed you "like ah fight down thing" ...nope I do not care to debate with you, save tutorials and schooling for others please.

I was unaware that I needed to be kindergarten specific in here, I assumed persons had that knowledge already. if you misunderstood what I said, then thats okay, we shall not waste time to debate.. I do not need to be more specific in my comments if you misinterpret them. cheers mate

[Aaron 2NR]

this link has some nice read ups with regards to the topic above.


http://forums.nasioc.com/forums/showthread.php?t=465249


i believe up to the 04 came with a forged subaru piston but it isn't as strong as an after market forge piston that you would put if you're building your block...


the newer engines have a Hypereutectic pistons

[JJ16]

this link has some nice read ups with regards to the topic above.


http://forums.nasioc.com/forums/showthread.php?t=465249


i believe up to the 04 came with a forged subaru piston but it isn't as strong as an after market forge piston that you would put if you're building your block...


the newer engines have a Hypereutectic pistons

Correct achan, I cannot recall if it was on 2nr or fb it was mentioned where I said in comparison to those aftermarket brand such as CP etc..they are not as strong, but nevertheless they are forged.

[JJ16]

Btw lance dont go getting your stuff in a bunch... I never said its a fact that you "like a fight down thing" or a "beat up chest" ... its unsubstantiated as far as you may see.....but likewise others may say its well supported... we each have our opinion... u aint always hadda measure your "knowledge" to play man.
.. #noimbert

[shogun]

Wow @ the condition of that engine.

[Lance]

No one's measuring knowledge to play man. Whatever that means.

I would have just like to see the thread keep to hard evidence given its title. Focused and evidence based debates.

There are enough unverified rumors going around regarding the engine and this has in part contributed to its dismal reputation. In my mind I saw the thread as a repository for hard facts.

But if this is sufficient then so be it.

[Lance]

Wow @ the condition of that engine.

I've seen this locally as well. I was helping a friend with a rebuild and he frequently used water on his cooling system. The case bolts heads were also rusted out and we were unable to remove them.

We went the extra mile though. Took it to a machine shop and drilled out the bolt heads. Once the halves were separated we removed the rest of the bolts.

[JJ16]

Well since sources (primary) sources rely on evidence, I guess you have not been shared with this primary source.

When you have free time (if possible), get a few STi motors... different years, different versions... after you've done so... scrap them all down... and take a nice close look (from the under section) of the pistons.

If you understand how forged pistons look, or how cast pistons look, this should assist you a bit with finding your evidence....

Cast pistons are cross hatched under the pistons, and forged are smooth... this is one way to identify..

weight may not always prove as a reliable factor....

Even on some forums you can find information.... even this one mate who decided to email Subaru...

But seeing how your stance is, this quote may stand or be seen as hearsay ...

QUOTE

"Here's my question to SOA:

YOUR ORIGINAL MAIL:

I purchased a 2004 STi last July, and have one quick question. I see
information on your website that states that the STi comes with forged
aluminum pistons. A well-know engine performance company disputes that
they are forged. My question to Subaru: Are the 2004 STi pistons
forged aluminum?

Here's their response:
Thank you for visiting the Subaru Web site and for your inquiry. The
2004 WRX STi is equipped with forged steel pistons and forged aluminum
conrods and crank.

Thanks for the opportunity to be of assistance. If you need any future
assistance, please feel free to contact us again."

[R. Mutt]

its a fact these engines weak when compared to its rival- the 4G63

And this is why I thought the discussion is necessary. Most break because of mechanical failure or errors with the tune which lead to failure.
...
I have personally seen a few local cars over 300hp on stock internals, mine included.

What about "bad" gas?

[Aaron 2NR]

well I'm a victim of it...along with an aggressive tune....stock internals aren't bulletproof....
the log a few days before showed the IAM was on 16 which basically means the ecu didn't have to do any corrections, retard timing etc and the tune was fine...the engine took a lot of hard jamming at events etc with the same tune so i honestly wouldn't say that lead to the failure of my engine....

a big lesson i learnt was filling up at a gas station that i'm not accustomed using...


actually have a friend who broke a built engine this week...fuel pump malfunction on full boost and broke a piston....

all part of racing

[Monk BANzai]

i quietly reading and learning/doh really contribute (As a former legacy owner).. question tho..... Wouldn't running Meth nullify any problems with octane? Regardless of tune?

[16 cycles]

^ depends on your trigger for the meth to start spraying

e.g. some use a boost threshold >7psi after which the meth/water injects progressively as boost increases....

anywhere under 7 psi, you relying on the ecu settings (tuned &/or un-tuned) and IAM to compensate for the quality of gas - hence if you tune for premium and get something far less at the pump, you increase risk of knock

[Aaron 2NR]

Yup mine was triggered at 5psi...

[R. Mutt]

You are not going to blow a motor at or under 7psi even on shitty gas with an ignition advance multiplier at 16 7 psi is baby load values....turbo is barely spinning and the pistons+rods are not seeing anything near the forces they see at 25psi (in regards to 16cycles point)

[R. Mutt]

What load/boost were you hitting when it happened?

You see I don't think it had anything to do with the gas or meth....I think one of two things: either mbt was exceeded or mbt was achieved and but there was too much torque at peak load. If the IAM is 16 that means the ECU is happy...no knock and indeed advancing the ignition. So bad gas can't be in the equation.

[Lance]

You are now going to blow a motor at or under 7psi even on shitty gas with an ignition advance multiplier at 16 7 psi is baby load values....turbo is barely spinning and the pistons+rods are not seeing anything near the forces they see at 25psi (in regards to 16cycles point)

X2 on this. A lot of guys actually run a very lean spool up because of the low load conditions.

[Aaron 2NR]

i downshifted into 4th at 3000 rpm and well wide open throttle, car hit the usual 22psi, i noticed the arf dropped to 11.6-11.9 then noticed the smoke..... (car is tuned at an afr 11.1)
the sample of fuel taken from the tank showed water in it that why it was suggested to be bad fuel that caused detonation....