97itr153

Who is your source? What effect do these kits have on the warranty?

If the warranty remains 100% intact, i will look into the 400bhp kit for my upcoming STI, and the 292bhp kit for my wife's wagon.

Overboosted STi

Wow!! A 400 HP kit for the STi? Thats really neat...I wonder how much the kit would retail for?

If I ever own an STi I'd like to push the car up to the 500-HP level. I wonder if that is attainable

Rudy

500 HP would be nice. I don't think it would be posible with the 2.5. Not for long anyway...

Nolift911

Considering the "built" nature of the internals of the 2.5 it should be good for 400 reliable hp on pump gas and maybe more I would think.

Things to consider are drivetrain...the gear box and clutch in particular.

Does Pro-Drive have a USA site up yet? Where are they based out of in the USA, if anywhere?

-Jeff
nolift911@hotmail.com

Rudy

The 2.5 has thinner cylinder walls than the 2.0. That would be my first concern pushing more than 400hp. The tran. and clutch would never handle that much power and would need to be upgraded first.

Nolift911

Thinner cylinder walls? Good point. Are you basing this on the change from 2.0 to 2.5 as a logical inferrence or have you heard something specific? Either way it is worth noting...

In addition, I was poking at the specs for the 2.5 in the STi...

for the block "specially reinforced dia-cast aluminum with integral cast iron cylinder liners, five main bearings, semi closed open deck design"

Cast iron cylinder liners is a good thing, not sure how that would play into the 400 hp issue. Does the regular 2.0 WRX have cast iron liners or is this unique?

Another thing of note is the sodium filled exhaust valves..which I think allow a higher rev range?

All that said I am not an internal engine expert but I think overall it is a good platform for adding more power, safely and reliably.

Rudy

The Local Subaru dealer informed me that it's the same block as the 2.5 in the RS, modified to handle the added HP. I guess we will just have to wait and see. I am sure someone like Cobb will do some R&D and try and build up the HP to 450 and beyond. I won't touch one till it's been proven.

Rudy

O, and yes, the 2.0 WRX does have Cast Iron Cylinder Liners.

RallyKeith

Sorry Rudy, please don't think I'm being mean or dissing your source, but once again this is what someone has been told by a dealer. What makes any of us believe what a dealer tells us when they don't know the price yet?

I don't see how this could be a modified NA 2.5 block. The NA 2.5 does not have a semi closed deck. The STi 2.5 has a semi closed deck. I don't think that is something that can be modified after the fact, plus I doubt Subaru would have designed it like that.

Here is an interesting link that shows what appears to be pitures of the 2.5 STi block. Later on there is another link to look at his stock EJ25 block. Notice the semi-closed deck on the turbo, and look at the thickness of the walls. It actually looks like the turbo walls are thicker, but who can tell.

http://www.forcefed4.com/

Let me make one last point. The thickness of the wall doesn't matter as much when you have a semi-closed deck. That is actually the purpose of the semi-closed deck. It holds the top of the cylinder wall in place so it doesn't move under the strain. The walls on a motor with out the semi-closed deck need to be thicker to help keep them in place. So this having thinner walls doesn't really matter that much with the semi-closed deck.

So anyway, my $.02 and some info to chew on! Like I said and so many others have, we just won't really know until Subaru releases it.

Keith

Rudy

I don't think he meant they took the engine out of a 2.5 RS and put a turbo on it with some mods. I do however believe that the block was molded after the 2.5 with major mods. As I said, we will just have to wait and see if it can handle 450+ HP. All I know is my STi will stay factory for at least a year or so till I am sure it can handle more HP. 300 will do just fine for now... :~)

RallyKeith

I agree with you on keeping it stock. Mine will stay stock until I run out of warrenty or it is paid in full. Also, I think someone else mentioned this but I also won't modify it until I have the money to fix / modify the tranny if it breaks. Something about watching the US Subaru Rally team changed Trannies at every event makes me worry.

Keith