I have supporting mods in place to run around 500, is anyone else running this much power? Who has the most power from a standard 2.5?

cheers.

 

500bhp 2.5 ???Thought 350 was enough then gasket failure pistons and so on...

 

hmmm its ran over 400 for 5 years, not been any problems.

 

you realy mean standard 2.5?? 500 will kill it imediatly

if its full of good stuff it can be done easily enough

 

running 400 isnt hard it may have been on a dyno at that but realisticaly how often does it get to that level during normal every day driving

400 and 500 are miles apart

 

QUOTE
Who has the most power from a standard 2.5?

No way will you run 500bhp on a standard 2.5 block. Standard these 2.5s dont like much more than 1.2 bar boost.

 

Yeah standard sti 2.5 engine with a gt30.

Does anyone run 450bhp then?

 

Daz was running 450 with gt30 on a standard 2.5 for a while

 

Yeah I did for around 10,000 miles before I sold the short motor on.

Ran 452bhp @ 1.5bar from a Rotated GT30R setup.

Consensus of opinion was that I was lucky to get away with it but the engine was in great condition when I sold it on.

If you can afford to rebuild it when (not if) goes wrong then go for it. My advice would be to atleast swap the pistons for some forged items first.

 

The stock block has seen over 500bhp but pistons are prone to cracking much after 400bhp. Rods are good for 500/500 but rpms need to be kept in check at that level.
500lbsft is seen as the upper limit for the stock liners but more has been seen if the cylinder pressures are kept under control. One knock will blow a liner at that level.

 

Is there much difference in price rebuilding before/after it blows up?

 

a lot of diference as you will have to repair damage and replace parts that you dont need to damage if you do it right now,
if you can do it pistons and liners make it future proof our linered 2.5 makes just over 600 on pump gas and has lasted 12000 miles with no dramas and trust me that car gets ragged

 

Very true and thats if its a true 400bhp??

 

yup,

Depends on the level of failure but worse case scenario, is you'll f*ck the block the heads and the turbo which will cost you thousands. A set of pistons prior to build will cost you about £600 tops. For me it's a no brainer. Fit some forged pistons, and keep things below 500BHP, you'll have a very very nice road car.

 

That will be the standard fit gt30 which never gets the figures they ever quote, no offence meant

 

none taken, mine is rotated.

 

Exactly what model subaru do you have?

Tony

 

p1

 

Ah ok just that they didnt bring out the 2.5's till late 05 so you had me
You owned the car for all 5 years? just that most of these earlier engines suffered from head gasket issues

Tony

 

No previous owner had it done

 

If 5 years ago then it had to be a block from the US 2.5 to be that old.

 

i wouldn't advisse 500 on a ej25 block anyway, some folks get away with it, some don't to variable when they go pop and split the bores. personaly i'd rather save my money and get it right first time. decent closed deck block and away you go

 

a 2.5 block with decent liners will easily handle 500 and more hp
liners are not a massive mystery and not hard to get done

 

liners are quite dear, but then again i can swear shaun with the spec c didnt have any relinering done neither did duncan. im at 500 and no problems at all. i think if its built well and mapped well then you will be fine.

 

getting 500 on a dyno and then driving at far less than that im sure it will be ok,
but what it does do is give no margin for error, and if you used full power often you may think different
as said earlier at that power any small detonation can cause a prety big falier,

we had ours unlinered and it was fine at 430 hp untill 1 day after a thrash it had enough and was suddenly very sick in an eye blink

with the liners its bullet proof at 600 and it gets abused at santa pod and on a local farm driven on full boost (2 bar) often with zero issues

remember not every mapper gets it dead right every time, no matter who they are,

thats my opinion and having had both with decent power the linered block has been far better

I bet you dont have standard pistons any more than we do and thats what the OP seems to want

 

i see what you mean, i have forged pistons and rods but hopefully the OP will change his pistons and can then run it near 500 with a sensible rev limit and hopefully he will be fine.



mus

 

Just had remap hit 450 @ 1.6 bar, pulls well haha.

 

500 on a 2Ltr STi is not unusual and it will run 400-420 all day long as it is a pretty strong bottom end but even on the 2Ltr you've got to watch the revs although redline is 7600 as std. IMHO 6900-7000rpm is plenty.

400 is par for the course with a std 2.5 but i've not heard of many if any running 500. The 2.5's redline as std at 7000, IMHO i'd have that dropped to 6500 to be safe at those kinds of outputs.

 

I use an OE standard 2.5 block case (not standard internals obviously), which is still going strong after three years of abuse. It has recently made over 600bhp!

Duncan's is linered.

 

Not questioning the strength of the 2.5 block itself but more the cast pistons. 2Ltrs run forged pistons hence the ability for some to run at 500bhp if the mapping is very good. The only thing with this is that at 500bhp+ regardless of the size of the block, you're running a fair bit of boost. Then you're worrying about the heads lifting off the block, specially making 600bhp. Very nice BTW