hi, just weighing up cost involved in modifying my forester sti to around 400/450.
i understand its an ej255 engine, its been mapped with the standard turbo 330/350.
what exactly would need doing to get to this sort of power and torque?
mileage on car is approx 60k running sweet atm.
car is a 2005 pre facelift 2.5 sti.

is it a full engine build or just change pistons,turbo,clutch and head gasket?
any info appreciated as always.

 

It all depends on how well you want to do it. But heres a write up scoobyclinic done.

 

 

thanks, so basically a big power forester is gonna cost big money. like you say, is it really worth it?

 

To do it well and have reliability and not have to rebuild again after 20k miles they yes ur talking 7-10k. Could get the power cheaper but could blow the engine at anytime. Get suspension sorted and then a remap for the fuel you use and to tweak the power bands e c then enjoy. I always have a dream of 500bhp subaru, fasted car before I got my sti was a 150bhp coupe so now with 300+ bhp I'm pretty satisfied I don't actually need more for everyday driving

 

 

already mapped etc.

 

yeah I get that, but now we are talking about a complete step up in power and torque. 400bhp 450ft lb.
would imagine it would make for a very rapid forester, but at 7-10k. no thanks lol

 

reliable power isnt cheap once you go past a certain point.

i can tell you 400/420 in a hawk saloon makes a great daily drive

 

I love the FSTI package, mine has surprised a lot of cars that should have been far faster than mine.


One of my friends has a modified hawkeye with a billet VF43, FMIC and loads of other mods mapped to 395bhp and he was unable to pull away from me at any speed. In fact I actually gained on him (just).


Just the other day some kid tried to race me in his modified convertible M3 (Very loud exhaust) and he couldn't get close to my FSTI. I was pulling away from him massively in all gears. It made it more funny because he was posing with 2 blonde girls in the car at the time.


Mine is still on the original VF41 and mapped 3 time snow by Andrew Carr with mods and gains every time. I love it.


Would love to have a go in a 450bhp FSTI to see what that's like. Realistically if mine ever blows up it'll get forged with CDB inserts, uprated rods, pistons etc probably by Paul Finch. But to go from 350bhp to 450bhp costs a lot more on top of the engine, I'd have to swap my 2.5" exhaust for a 3" system, downpipe, FMIC, new turbo, fuel delivery etc. Just not worth it for a car that drives so well as an every day road car at 350bhp.

 

clinics done a couple of the uk turbo'd ones up to 450 hahahaha

 

hi andy, have you had yours on a dyno yet? can you list mods and bhp/torque figures.
martyn mapped mine as you know, turbo max out at 330/350 1.4 bar or thereabouts.

 

Sadly still not been on a rolling road. Was supposed to be doing a local rolling road day last weekend arranged by a local group who cancelled it without notice to do a Prodrive tour instead. Only found out a couple of days before it was cancelled. Very annoying.

 

 

in what way is a forged 2.5 a ticking time bomb?

 

You mean from the dealer? which are simple refresh using same parts so liable to fail again.

I Don't know of many 2.5 failures post forging unless they had genuine part failures, had crap treatment or just been crap builds.

Given how many I've had and how long I've been around 2.5's that have been rebuilt I suspect you may have a rather limited view on them.

 

if its mainly crap rebuilds then the fact it's a 2.5 is irrelevant, any crap rebuild will likely fail. a crap map will kill any car as well.

why single out the 2.5?

Sounds like you've had a bad experience?

 

I'd be inclined to say it's a bit of a and b, quality of the rebuild and the inheritantly weaker 2.5 block (cylinder wall is thinner) that is more likely to expose the poorer rebuilds.

For head gasket failure, it took me 3 goes to get a stable build on my hawk 2.5 running at roughly 400hp with a td05 20g. On the last one I machined both the heads and blocks (instead of just the heads as was done previously), fitted the uprated JDM water pump and a mishimoto rad to improve cooling. I also run almost stock fuelling and timing for safety. (This is additional to forged rods and pistons, arp studs that were already fitted previously)

I've found it best each time to completely strip the engine, even for h/gasket failure and that's where the cost comes in, unless you can/are able to do it yourself.

 

i've never had issue on any of mine, although they are pro builds.

 

So was my first one, then I lost faith after having spent 4k on it...

 

if you'd have said to me full forged build for 4k i'd have said thats cheap. May explain it.