Hi , I have a standard 2.5 sti can anyone let me know how to get more BHP what route to take what can be done DIY and what i have to get done by specialists and do i have to upgrade any of the drive train cheers dave

 

Hi,

Your drivetrain will be fine for 500+ bhp,
Your 2.5 block on the other hand is not, If it is still standard a re-map will release quite a bit and should see you on 340bhp /350+ torque, Not sure on exact numbers but the 2.5`s can have issues with headgaskets and even piston ringland issues on the 08 plate onwards, Dont hold me to it but i wouldnt suggest going too mad with it unless you change some internals, So in standard barring exhaust,turbo swap i would cap it around the 400 bhp mark, Even this might be a little much for longterm reliability,

Gaz.

 

All those 2.5 STi engines suffer the same Gaz (the map was a little more agressive on the hatches though), I would cap it at around 350/360bhp unless you want to rebuild the engine?

Tony

 

Had ringland failure on my 06 SpecD running 345hp 385lbft torque (remaped 3 inch exhaust sportscat and filter) Head gaskets were fine, std clutch held up well.
Good excuse for a forged rebuild!

 

2.5 motor is the limiting factor.

OEM - don't run no more than 350-370.

Built/decent forged pistons - no more than 450.

 

Piston and rods... More power than your wallet can handle...

 

thanks for you replys were is the best place to go for re-mapping in cheshire

dave

 

But isn't there still an issue with the lack of metal between cylinder bores? Hence 'only' running 450 odd. That's why I didn't necessarily mention a rods change (although, I accept that if you were going to forge, most people would do the rods too, as matter of course)...

 

It has been said to me that a completely standard EJ257 block is good for 600+ , i cant remember who said it but it was definately someone who's opinion is worth trusting, it's one of my past threads/posts, i think any further mods are just insurance, how the open deck block compares to the SCD block i have no idea.

 

Will handle 600bhp,but you will need get block pinned and for this i would suggest too 14mm ARP studs


Jura

 

Nope, that was my exact question infact, about the pinning, agreed stronger head fixings would be required, will try to find the post...

 

What exactly is "pinning"? Why does it allow you to run much more power on the relatively 'weak' 2.5s?

 

Pinning is a metal rod which is inserted between the outer bore wall and the inner casing wall to provide additional strength/support



i found the post i was talking about aswell...

 

Ask Daz,he run his pinned 2.5L,something like this





And this thread hope so will answer your questions

http://bbs.22b.com/cgi-bin/ultimateb...=005745#000032


Jura

 

Those pic's pain a thousand words, ta.

Yeah, I knew dazdavies had had his done.


But.... surely a 2.5 CDB would sort out any 'weakness' issues, then? But prob too dear for Subaru to produce?

But enginetuner ^^^ doesn't seem to have a problem with their 2.5 builds, anyway!

 

Subaru have released a new 2.5ltr (and 2ltr) engine, not sure on its dimentions but hopefully the 2.5 isnt just a bored out 2ltr like the last one was

Tony

 

Yeah, fully stroked for the extra 500cc - if that's physically possible(?) - would do it.

Or at least a combo of a bit less bore and and a bit more stroke.

 

Indeed, Litchfields are converted to CDB iirc and some people take EJ22T's out to 2.5l, neither of which are cheap routes to a strong block though, i think a pinned SCD block is a sensible way to go for a bit of insurance, have it pinned then bored/honed with a torque plate fitted and hope for the best...

When you think of it how many people truely run OVER 600bhp and use it all...

 

Remap and straight through decat exhaust.

 

Ej20 can be stroked to a 2.7 Joz...
http://www.tonyrigoliperformance.com...e_engines.html

 

Didn't know that thought the ej20 could only go up to 2.2 bored but with stroke go to 2.35.

Thats cool

I know the ej25 can go up to 2.7 because its slightly bigger.

 

jollygreenmonster for your mapping mate

 

On pinned 2.5s is there any chance of the 'pins' working loose, etc.?

 

exactly what ive had done !!!

 

Nossy, the engine is the same physical size as a 2ltr, hence why it has so many issues
Not sure on the new 3rd gen engines though, not that many details about the 2.5ltr v 2ltr on that front as yet

Tony

 

I believe the pins wont as those will be held firmly in place, the liners can slip though.

Tony