One that would have proper forged piston, good rods etc etc.

I have been told the US ones come with crappy pistons, that cant really handle lots of boost.


So just for a bulletproof block, what kind of money are we talking?

 

to do the bulletproof 2.5 you need to use a 2.2cdb or 2.0cdb at a push i think. The normal 2.5s like mine are semi closed deck blocks with thin cylinder liners, so although mine can be termed "built" it still has the weak cylinder liners. It should still be able to to 1.8bar though, although 1.6 would be a safe limit.

On a regular 2.5 from the states then about 1.3bar would probably be a sensible max....

in terms of cash for it? they arent cheap.....you need to ask yourself if your needs really justify it, as if its just a regular road car, not tracked, just driven normally then a normal 2.5 may suffice....

you do lose some of the "oooomph" factor on a 2.5 by the way, unless you have a mahoosive turbo.

 

Well seeing as my engine is fine atm, there is no rush, i was thinking of maybe getting a 2.5 block and slowly building it up in my garage, I have no experience at all of doing it, but like i said im in no rush.

It may just be an idea, but it would be a real achievment if i put my mind to this and pulled it off.

 

i totally agree and fair play if you did do it.....id like to do a similar thing with a D16 honda engine and turbocharge it, but i dont have the space.

I think for a hardcore 2.5 build though you would need a lot of machining tools to hone all the parts....its not just a throw it together job i dont think

 

How much power are you aiming for ?


Mark.

 

Not really got a figure in mind, I was just thinking of a well built, reliable engine thats gonna hurt my neck

 

LOL! Self inflicted whip cash!!

 

What kind of specialised tools would i need, could i maybe just transport the block to a local engine builders im friendly with to do whats needed?

 

I'd say for circa 450bhp/450ftlbs, the standard block is good for the job.

There are quite a few cars running with this, and some with a fair bit more power without issue.

Well set up, it would be more than capable of hurting your neck, if that's what you're into


Mark.

 

What block do you mean by the standard one?

This is the first time i have started poking around with the 2.5 idea.


Also what kind of cost are we talking? inc turbo

 

Mark at the last few words !!

 

the turbo to properly snap your neck will cost you a fair wedge, if bolt on, budget at least 1200 quid, if rotated double it by the time youve bought all the ancillaries and neccesaries...

there are more and more turbos out there that are more than capable on the 2.5 nowadays, the 20g for good response, and then the GT30 hybrids such as the MD321T,L like mark supplies and the one i have which seems to work ok for me

The 321T being the pick of the bunch from people that have had experience of them.

 

I keep reading about rotated turbos, why would you need to do this, is it just a case of lack of space?


I really think im going to be doing a LOT of overtime this coming year

 

And yes 450/450 would be nice,

 

a rotated turbo setup allows the use of a FULL garrett turbo, not a garrett core that have been forced in to the standard impreza turbo position. Using the full garrett housing is what the core is designed for and as such it performs much better in most cases.

for example, the core in my turbo is larger than that of a "true" GT30R, 55lb/min max flow vs 53lb/min flow. Yet the full GT30R with the smaller wheel is capable of producing around 100bhp more than my turbo.....THAT is the difference.

 

Starting to make sense now, are Garette really the turbo to go for then.

 

Cue Mark hes the man to explain to you about turbos...

 

What size injectors will be needed for a build like this?

Will just the one Walbro Fule pump be enough?


Im thinking of maybe forgetting the STI pinks i was after for my first stage of tuning, and getting some huge ones that are more than adequate, and they can then be reused for this build.

This aint gonna stop with the engine build is it, im now thinking also of gearbox/clutch.

The list is growing with every post

 

unless youve got a target or a budget then think very carefully.....

it can and will get very expensive, ive done a few things the wrong way round and have regretted it and learned the hard way. To get the most out of a 2.5 youll need to change the majority of the car, and thats the end of it. Engine, gearbox, clutch, turbo, injectors, intercooler, brakes, the list goes on....

Id recommend not bothering....sounds odd i know, BUT, have you driven say a 350bhp car? if not, and knowing roughly what your car is, then you would be surprised at how different they are to yours.

Id recommend getting the most out of your 2.0 first with say....a VF34 and the pinks and an STI cooler.....the difference will be night and day just from that.

If down the line you fancy more? then think about it.

Dont make the jump from say...260 to 500...youll kill yourself.

(if you wanted my opinion!!)

 

By standard block, I mean standard 2.5lt block, but you would need up rated pistons, and rods, IMHO.

You really don't need to go for a rotated Garrett turbo, unless you are aiming for some way over 450bhp. Personally, I don't think it's worth going rotated until the aim is 500bhp +.

Some of the current Garrett GT series ball bearing based bolt on turbo's are performing so well, making great power & torque, and with fantastic response, it's hard to justify going rotated unless you want silly power.

I'll PM you some details.


Mark.

 

so standard as in what i have, a standard 2.5 block, with pistons and rods combo (in my case CP pistons and Eagle Rods)

Think ill have to try and push those boundaries at some point mark

 

thanks Mark

 

I have that exact setup and am getting 333bhp & 325lbs, cookstar if you want to test drive mine your more than welcome

 

I had that in mind when i was typing that Ian

 

I think it would be a good idea if i did feel what 330 ish felt like, where abouts do you live mate.

 

Eltham SE London, just about 10mins from the Dartford Tunnel

 

So a tunnel run would be obligatory

 

Oh yes

 

Sounds like a plan mate, really appreciate this

 

This is an interesting thread...

There are a few of us with FSTi's who would like to know costs involved in making a 350+ reliable...

The Cosworth engine seems an expensive overkill, especially when we have a brand new 2.5 to start off with...