I've read the semi closed deck block is more vulnerable to failure than the 2.2 closed deck.

It seems that a bare STi block sells for about 300-400 and a bare 2.2 block sells for about 1200-1300, however the STi block is much easier to find than the 2.2.

So, what can be done to make the 2.5 as reliable as the 2.2 and what does it cost?

 

Don't think it will ever be as reliable as the 2.2 but pinning it certainly goes a long way to helping

 

AS performance for a closed deck insert!

Still probably not as bomb proof as the 2.2's as inevitably the larger cc means thinner liners, but still alot more than most peoples wallets and aspirations!

the extra cc means more torque ..... which is nice! :-)

 

Alyn@as performance will machine the block and make it closed deck for not a lot of money (compared to block failure etc)

Over the pond it seems liners are popular, but they haven't caught on in the uk for whatever reason.

Both solutions will make the block a lot stronger.

 

The reason why I ask is Ali Afshars 8 sec impreza runs the 2.5 and I was wondering how he made it reliable with 1200whp.

 

I supply new blocks, info here-
http://cgi.ebay.co.uk/ws/eBayISAPI.d...e=STRK:MESE:IT

Why not use an 83mm billet crank in an ej22t block to make a 2.5 :-)

 

Any mods needed to the block to fit the 83mm crank?

 

What's this de-stroking a 2.5 all about then? Read a lot of the boys over the pond doing them, any body run one over here?

 

Drew over on 22b runs a de stroked 2.5, making it into a 2.35. He has one of Alyn's closed deck 2.5 block and is running a billet gt35 around 600ish with no issues so far

 

They sound quite interesting lol, what does his rev to now banny as I read it ups the rev range and holds on to the power longer, is that the case? They seem to love them over the water and some mad build designs, always here a lot of the stroking engines route over here but not so much of de-stroking

 

Pretty sure he is on jdm avcs heads and is revving to 8k, andy f is mapping it again soon will get him to post his graph up on here but goes well at the top end

 

Cheers banny, ill have a gander over at 22b now aswell

 

Yes, it's not a staight forward bolt in job like the 79mm crank, ive got special length I beam rods and the block needs some machining to allow the crank to rotate. Ive built a 2.0 with an 83mm crank to give 2.25, that worked well, and ive just built someone a 2.6 stroker which should be on the dyno soon. Ive also got a 2.6 underway for my own JDM Bug STI (new project thread). I'm sure it will make a great set-up in a 2.2 block, if I can find a block I may do that for the Bug instead
I don't really see the point in de-stroking a 2.5, as everyone raves about stroking a 2.0 (2.1) at the end of the day, extra stoke will always give better torque?

 

will be interesting to see what kind of figures the 2.6l motor will make once on the dyno.i can imagine the torque will be very high.

 

Yes it should be good, ive built it for a Customer of another tuning Company, the design brief was to achieve 450-500bhp but minimal lag and big mig range, its on JDM AVCS heads with RCM cams and high compression. It will be interesting to get her on the dyno, I was going to run a project thread but as its not my own engine it wasn't possible.