32 replies to this topic

[skillionaire]

Hi,

Do you really think you're the only one in the world that understands percentage breakdowns?

Apologies for making you come here and endure our lesser intelligence.

Is it true that you can further strengthen a hyper eutectic alloy through processing?

Cheers,
Nik

[Soop]

Ah no, thats not what I meant at all. What I mean is, its a little bit redundant. Its basically pointless information, if you're purchasing pistons for a rebuild use a quality provider and they'll almost certianly comply with ANSI standards. Without knowing who the the suppliers is for Fuji heavy industries the ANSI standard is a useless document.

[skillionaire]

Hi,

Americans love to regulate things.

You probably missed my edit, but is it true that you can increase the strength on a hyper eutectic alloy? If so, do you think this process could be applied to a B4 piston? Or probably become a cost prohibitive exercise?

Cheers,
Nik

[BigWillieStyles]

From where?

Are you able to provide some reputable sources to this?

We need to cut down this 'I have heard' 'I have read' non sense.

I have heard that STi pistons are actually painted pink.

Doesn't make it true.

Back up your claims with REAL evidence or do not post. We do not need to help in the spread of falsities.

Thanks for being so aggressive. Heres some links -

Rexnet
scoobymods
nasioc
mrt forums
wrx aus forum
rexnet
mrt performance of sti overview
perth wrx

[Dylan]

Thanks for being so aggressive.

Rexnet
scoobymods
nasioc
mrt forums
wrx aus forum
rexnet
mrt performance of sti overview
perth wrx

It wasn't that hard to provide some citation was it ? If you are capable of searching and looking at all those forums, surely you understand the amount of incorrect information that is out there - and the amount of things people say are true despite having just heard them from old matey down at the corner garage ?

Appreciate the effort mate - thank you.

[Soop]

Hi,

Americans love to regulate things.

You probably missed my edit, but is it true that you can increase the strength on a hyper eutectic alloy? If so, do you think this process could be applied to a B4 piston? Or probably become a cost prohibitive exercise?

Cheers,
Nik

I Owe you an appology, I madde a mistake re: Hypo/hyper-eutectic definitions. You're correct it is the silicon content that defines the classification.

As for "increasing strength" it's a little redundant with standard components. But you can look into things like shot peening, heat treating a cryogenic treatments to improve/change the molecular bonding.

[Soop]

Thanks for being so aggressive. Heres some links -

Rexnet
scoobymods
nasioc
mrt forums
wrx aus forum
rexnet
mrt performance of sti overview
perth wrx

Frankly, I wouldnt consider hersay regurgitated on other forums to be credible evidence either.
Not saying that's the case here but, There's allot of rubbish perpetuated on the internet, because unfortunately king trolls can make up the information as they go and no body will dispute it for fear of retribution. This is the down fall of internet forums. So anything take from a forum should be taken with a grain of salt. And I expect my posts to attract the same attitude.

[XXB4XX]

so does my GT come with hypocritical pistons too or what?

[Dylan]

Frankly, I wouldnt consider hersay regurgitated on other forums to be credible evidence either.
Not saying that's the case here but, There's allot of rubbish perpetuated on the internet, because unfortunately king trolls can make up the information as they go and no body will dispute it for fear of retribution. This is the down fall of internet forums. So anything take from a forum should be taken with a grain of salt. And I expect my posts to attract the same attitude.

This is true to a degree as well, but if it can be 'verified' from multiple sources, I guess you can give it a little bit more credibility (nothing to say that they all didn't stem from one 'incorrect' post though).

[Soop]

This is true to a degree as well, but if it can be 'verified' from multiple sources, I guess you can give it a little bit more credibility (nothing to say that they all didn't stem from one 'incorrect' post though).

This is the problem with forum posts.
If someone were to take the post in this thread stating that 06+ STi's had hypereutectic pistons as fact, and spread that on another forum. You have multiple sources of information all steming from the same source.

I'm doing a bit of research at the moment regarding hypo/hyper and plain eutectic pistons at the moment. So I will share my findings a little bit later.
Although for any real performance application I would recomend forged internals. And they're easy to tell apart. (the old tink and thonk test)

[Soop]

Okay, very very very basically.

Hypo/Hyper/eutectic alloy describes the silicon to alloy ratio of the material. Regardless of piston manufacturing proccess.

Hypoeutectic means it has a a silicon to alloy ratio of around 10:1.
Eutectic means it has a silicon to alloy ratio of 12.5:1.
Hypereutectic means that it has a silicon to alloy ratio of around 16-18:1.

Either material can be used as a cast or forged piston.
The silicon content effects the expansion rate of the material as the material temperature heats up. So basically if you've got piston slap you've a low S:A ratio.

There are clearly other ingrediants in the alloy mixture which can play a BIG role in determining how the alloy will perform, but this thread so far has been about silicon content.

[XXB4XX]

aren't all suby's well known for piston slap?

[Soop]

Not as far as I'm aware.

Most all NA subaru's sound alright.