2.5 Liter STi tear down (pics, 56k nono) - Page 2

totoherbs · 01-25-2004, 04:55 PM

Quote:

Originally posted by eightballrj
woh woh woh, I thought that the consensus WAS that the STi rods WERE forged... I thought that the pistons were too, but that seems to be wrong. Well, if the rods are also cast, then it seems that the STi shortblock might not be much of an upgrade at all for us WRX guys... Whats the deal guys???

RJ

Why wouldnt it be a better upgrade?? Better pistons, better rods, re-inforced deck and .5+ L...

Just because the pistons arnt forged doesnt make them crap, subaru went to cast pistons for a reason. And I dont see anyone saying the rods are not forged just that they "look less beefy" but they are still a good design... Quirt has said before in that the pistons and rods are the nicest parts of this motor.

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8Complex · 01-25-2004, 04:56 PM

Quote:

Originally posted by eightballrj
woh woh woh, I thought that the consensus WAS that the STi rods WERE forged... I thought that the pistons were too, but that seems to be wrong. Well, if the rods are also cast, then it seems that the STi shortblock might not be much of an upgrade at all for us WRX guys... Whats the deal guys???

Welcome to the real world, not the world of internet geeks only looking at advertising brochures to determine how an engine is made.

The upgrade comes in the semi-closed deck and extra displacement. The downgrade comes in the hypereuctectic pistons and the thinner cylinder walls. I honestly believe that the 2.5 is stronger, despite the differences.

djt81185 · 01-25-2004, 05:02 PM

forging is stronger than a casting...but heavier because there is more material in a forged product. Also the material in a forged product had an aligned grain structure compared to the casting which is basically a cluster**** by comparision.

Dan

roybfr · 01-25-2004, 07:47 PM

I don't see how the pistons and rods would be a down grade comparded to a USDM WRX.

srf · 01-25-2004, 09:28 PM

Then to see if they're forged can't you just look at the grain structure & measure the density?

Invisiguard · 01-25-2004, 09:32 PM

I dont see anywhere where it was even hinted that the STI rods were not forged, just comparing sizes to an RS rod . Also, ounce for ounce forged will be much stronger than regular cast, so dont let the actual size of the STi rod next to the RS rod throw you off

hatchy · 01-26-2004, 01:48 AM

Excellent pics, thanks Mike. Can we not turn this into a forged piston thread, please?

The sleeves looks pretty beefiy to me, the only thing that looks odd is the thin side bracing of the sleeves. I wonder if that will become a point of weakness.

pio!pio! · 01-26-2004, 03:20 AM

Quote:

Originally posted by 8Complex
You should probably specify which side... towards the end of the wrist pin, or towards the skirts.

I'm mostly interested in seeing a clear view of how much space there is between the top of the piston and the first ring

MJU1983 · 01-26-2004, 03:32 AM

Quote:

Originally posted by pio!pio!
I'm mostly interested in seeing a clear view of how much space there is between the top of the piston and the first ring

Invisiguard · 01-26-2004, 01:23 PM

Quote:

Originally posted by pio!pio!
I'm mostly interested in seeing a clear view of how much space there is between the top of the piston and the first ring

more pics and info on our pistons from you-know-where

http://www.aps-wrx.com/us_spec/subar...ns/pistons.htm

totoherbs · 01-26-2004, 01:33 PM

Quote:

Originally posted by Invisiguard
more pics and info on our pistons from you-know-where

http://www.aps-wrx.com/us_spec/subar...ns/pistons.htm

Dont forget the old thread on the block.

http://forums.nasioc.com/forums/show...sti+block+info

hatchy · 01-26-2004, 02:54 PM

Hmmm why does the USDM 2.5L pistons on APS' website look like the skirts are coated with somethiing and the ones from Mike's pictures look like they aren't coated?

Conduit · 01-26-2004, 03:39 PM

Internet racing or not, Subaru is still claiming they have forged rods and pistons in some sales literature. That's a problem, yes indeedy do. I'm certainly not going to complain.

BoostdBoxer · 01-26-2004, 03:44 PM

It dont matter to me I am hving my Block bulletproofed with Ductile Iron T-Sleeves in the next few months so I will be able to run 40 PSI of boost. Oh yeah my pistons and Rods are all going to be top dollar forged materials. And I want to get a new crankshaft but I am not sure about that one yet. I have been saving forever to get this done,

With that said and done I better save 10,000 more dollars so I can replace my tranny once I put 40 PSI of boosted energy through LMAO

realistically I will never run that much maybe 25-30 MAx but I want to have it built so it can take 60 before exploding and killing every living thing in a 12 mile radius.

totoherbs · 01-26-2004, 03:47 PM

Quote:

Originally posted by BoostdBoxer
It dont matter to me I am hving my Block bulletproofed with Ductile Iron T-Sleeves in the next few months so I will be able to run 40 PSI of boost. Oh yeah my pistons and Rods are all going to be top dollar forged materials. And I want to get a new crankshaft but I am not sure about that one yet. I have been saving forever to get this done,

With that said and done I better save 10,000 more dollars so I can replace my tranny once I put 40 PSI of boosted energy through LMAO

realistically I will never run that much maybe 25-30 MAx but I want to have it built so it can take 60 before exploding and killing every living thing in a 12 mile radius.

have you looked at the axis and i-speed blocks?? might be cheeper to get it from them then to have a shop build it.

Conduit · 01-26-2004, 04:26 PM

Quote:

Originally posted by BoostdBoxer
It dont matter to me I am hving my Block bulletproofed with Ductile Iron T-Sleeves in the next few months so I will be able to run 40 PSI of boost. Oh yeah my pistons and Rods are all going to be top dollar forged materials. And I want to get a new crankshaft but I am not sure about that one yet. I have been saving forever to get this done,

With that said and done I better save 10,000 more dollars so I can replace my tranny once I put 40 PSI of boosted energy through LMAO

realistically I will never run that much maybe 25-30 MAx but I want to have it built so it can take 60 before exploding and killing every living thing in a 12 mile radius.

I can't wait to see the headwork required to flow what you would need to support 40psi.

totoherbs · 01-26-2004, 04:31 PM

Quote:

Originally posted by Conduit
I can't wait to see the headwork required to flow what you would need to support 40psi.

You dont need huge ports to flow 40psi... just a turbo to push it in there. There are people on this board pushing 30psi on stock 2.2 block with 98 DOHC heads.

MJU1983 · 01-26-2004, 05:48 PM

Quote:

Originally posted by hatchy
Hmmm why does the USDM 2.5L pistons on APS' website look like the skirts are coated with somethiing and the ones from Mike's pictures look like they aren't coated?

Yes, I noticed that as well. I also noticed that the JDM ver8 pistons that I have look almost identical to the US STi pistons (as far as similarities go). Which makes me wonder if they changed the pistons in all STi motors recently. As the older ver7 jdm sti pistons were definitely forged (look at APS comparison shots).

Ill post some pics up later tonight of some JDM sti pistons I have.

-Mike
www.axispowerracing.net

Invisiguard · 01-26-2004, 05:52 PM

Quote:

Originally posted by MJU1983
Nothing special, but some people like to see whats inside of what they have

This block is getting sleeved, and we are replacing the rods/pistons w forged upgrades. Its for a customer in the Netherlands.

-Mike

Is he still going to run the stock cast crank?

totoherbs · 01-26-2004, 05:58 PM

Quote:

Originally posted by MJU1983
Yes, I noticed that as well. I also noticed that the JDM ver8 pistons that I have look almost identical to the US STi pistons (as far as similarities go). Which makes me wonder if they changed the pistons in all STi motors recently. As the older ver7 jdm sti pistons were definitely forged (look at APS comparison shots).

Ill post some pics up later tonight of some JDM sti pistons I have.

-Mike
www.axispowerracing.net

Well on some info its been show that the ver 8 jdms use cast vs the ver7s forged.... but that might start a huge flame fest again.

MJU1983 · 01-26-2004, 06:00 PM

Quote:

Originally posted by totoherbs
Well on some info its been show that the ver 8 jdms use cast vs the ver7s forged.... but that might start a huge flame fest again.

Yeah I just thought of that when I was sitting down playing a riveting game of Tiger Woods 2004. I’m like, hmmm the ver8 pistons look just like US STi pistons. Yet the ver 7 look nice and forged.

Ill post some pics up later, but I think we are all out of ver 7 stuff. Only have ver 8 to show.

-Mike
www.axispowerracing.net

MJU1983 · 01-26-2004, 09:28 PM

Some pics.. Again notice my awesome paint skills

-Mike

Pictures:
1st pic is Ver 7 STi piston from APS website

2nd Picture is Ver 8 STi vs. ROSS forged piston.

3rd picture is of the underside of both... NOTE the similarities to the USDM STi piston with the JDM 2.0 ver 8 STi piston.

4th picture is of JDM ver 7 STi piston from APS.

Interesting eh.

spiralsmurf · 01-26-2004, 10:39 PM

the usdm sti does not have forged pistons, this was a known fact long ago.

totoherbs · 01-26-2004, 11:00 PM

Quote:

Originally posted by spiralsmurf
the usdm sti does not have forged pistons, this was a known fact long ago.

Well to some of us... but others just refused to belive.

StiDreams · 01-26-2004, 11:16 PM

Now it looks like no new STi have forged pistons. I remember reading somewhere that the WRC cars also switch to the HE pistons. Is that true?

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01-25-2004, 05:02 PM	#28
djt81185 Scooby Newbie Member#: 34682 Join Date: Mar 2003 Location: Champion, PA Vehicle: 2012 F150 Egobewst Red	forging is stronger than a casting...but heavier because there is more material in a forged product. Also the material in a forged product had an aligned grain structure compared to the casting which is basically a cluster**** by comparision. Dan

01-25-2004, 07:47 PM	#29
roybfr Scooby Specialist Member#: 14456 Join Date: Jan 2002 Chapter/Region: MWSOC Location: WDM Iowa Vehicle: 09 BMW 335i Sedan 69/72/01 Corvettes	I don't see how the pistons and rods would be a down grade comparded to a USDM WRX.

01-25-2004, 09:28 PM	#30
srf Scooby Specialist Member#: 50646 Join Date: Dec 2003 Chapter/Region: NWIC Location: Bothell, WA Vehicle: 2004 WRX STi Java Black	Then to see if they're forged can't you just look at the grain structure & measure the density?

01-25-2004, 09:32 PM	#31
Invisiguard Scooby Specialist Member#: 43201 Join Date: Sep 2003 Location: SF Bay Area Vehicle: 04 STi 07 Corvette	I dont see anywhere where it was even hinted that the STI rods were not forged, just comparing sizes to an RS rod . Also, ounce for ounce forged will be much stronger than regular cast, so dont let the actual size of the STi rod next to the RS rod throw you off

01-26-2004, 01:48 AM	#32
hatchy Scooby Specialist Member#: 36852 Join Date: May 2003 Location: North West Vehicle: 2004 STI	Excellent pics, thanks Mike. Can we not turn this into a forged piston thread, please? The sleeves looks pretty beefiy to me, the only thing that looks odd is the thin side bracing of the sleeves. I wonder if that will become a point of weakness.

01-26-2004, 02:54 PM	#37
hatchy Scooby Specialist Member#: 36852 Join Date: May 2003 Location: North West Vehicle: 2004 STI	Hmmm why does the USDM 2.5L pistons on APS' website look like the skirts are coated with somethiing and the ones from Mike's pictures look like they aren't coated?

01-26-2004, 03:39 PM	#38
Conduit Scooby Specialist Member#: 6162 Join Date: Apr 2001 Chapter/Region: South East Location: Orlando, FL. USA Vehicle: 2002 WRX MBP, 1st WRX Ever in FL.	Internet racing or not, Subaru is still claiming they have forged rods and pistons in some sales literature. That's a problem, yes indeedy do. I'm certainly not going to complain.

01-26-2004, 03:44 PM	#39
BoostdBoxer Scooby Newbie Member#: 53163 Join Date: Jan 2004	It dont matter to me I am hving my Block bulletproofed with Ductile Iron T-Sleeves in the next few months so I will be able to run 40 PSI of boost. Oh yeah my pistons and Rods are all going to be top dollar forged materials. And I want to get a new crankshaft but I am not sure about that one yet. I have been saving forever to get this done, With that said and done I better save 10,000 more dollars so I can replace my tranny once I put 40 PSI of boosted energy through LMAO realistically I will never run that much maybe 25-30 MAx but I want to have it built so it can take 60 before exploding and killing every living thing in a 12 mile radius.

01-26-2004, 09:28 PM	#47
MJU1983 Scooby Specialist Member#: 14364 Join Date: Jan 2002 Chapter/Region: MWSOC Location: Saint Louis, MO Vehicle: 2003 WRX, '06 Armada 05 Vette & 05 STi (sold)	Some pics.. Again notice my awesome paint skills -Mike Pictures: 1st pic is Ver 7 STi piston from APS website 2nd Picture is Ver 8 STi vs. ROSS forged piston. 3rd picture is of the underside of both... NOTE the similarities to the USDM STi piston with the JDM 2.0 ver 8 STi piston. 4th picture is of JDM ver 7 STi piston from APS. Interesting eh.

01-26-2004, 10:39 PM	#48
spiralsmurf Scooby Specialist Member#: 16085 Join Date: Mar 2002 Chapter/Region: SCIC Location: Chatsworth, CA Vehicle: 2005 STi Black	the usdm sti does not have forged pistons, this was a known fact long ago.

01-26-2004, 11:16 PM	#50
StiDreams Scooby Specialist Member#: 26315 Join Date: Oct 2002 Chapter/Region: BAIC Location: On the grassy knoll. Vehicle: 07 Outback Silver/Silver	Now it looks like no new STi have forged pistons. I remember reading somewhere that the WRC cars also switch to the HE pistons. Is that true?