white

Planning on the PS 340 upgrade on my MY06 STI when it arrives shortly (obviously after letting it run in for a bit) but I am concerned as to the reliability of the engine at this level, mainly because of reading about those hypoteutetic cast pistons being a weak point.

Maybe I'm just being over paranoid, I don't know but I would just like to hear peoples thoughts and opinions regarding this issue.

I know that PS would not sell a package that would have issues with reliability but still, you can't help but be cautious.

Would it be worth changing the pistons for some forged items or not??

But then again I remember reading an issue of J-Tuner where there was some company in Malta (I think) running just over 400BHP on standard internals of an MY05 STI, so maybe I am being paranoid.

p1mark

you will be fine at 340BHP

pippyrips

Mine has been running over 340BHP tuned by PS for 2 years - has skipped a beat so far (touch wood!)

jd5217

your 06?

TonyBurns

iTrader: (3)

Couple of points, the hyperheuetic pistons are stronger than the old forged ones that were in the previous models, they suffer more if you det the engine though but the new ecu's should retard better so that shouldnt be a problem either.
I know of several 360bhp JDM models with hyperheuetic pistons which have no problems running that sort of power, some have even more than that.
The other point is that if you do go the PS way, you invalidate your FULL subaru warranty, just to let you know as the increased performance will effect the whole of the car and not one specific point.
If you are happy with this then take that route, but if you have issues with reliability (which you shouldnt) then go the PPP, which may acutally suit you better as what ive heard is that it puts out a little more than whats quoted

Tony

white

Thanks Tony and thanks to everyone else who has posted, you've put my mind at ease

I know what your saying as regards te warranty. I'm still thinking about this TBH but will probably end up going the PS route along with the T25 handling kit. All in good time

MikeWood

white

During the 06MY STi PPP development we saw 340-350bhp with a downpipe fitted along with the other PPP components. We haven't released that spec but have released a version quoted at 320ps....................

Mike

p1doc

next limited edition model by any chance?
martin

T5NYW

iTrader: (4)

Is it a MY06 2.5ltr UK/EU or JDM 2.0ltr?

MY05 was a 2.0ltr

I agree I doubt if they'd just produce a package that would't last. My MY06STi runs very nicely at 350bhp 350lbs IMHO

2.5Ltr PPP is 320ps As Mike said the Torque fiqure was about 340lbs IIRC so performance would be fairly simular. Prodrive have to produce a "Off the shelf" map to suit every Car with reliability. Whereas PS remap on a rolling road and able to tweak setting percific to the quirks of your car.
IMHO if you have a

MY06 2.5Ltr and want 360bhp and reliabilty.... Probably Yes
MY06 2.0Ltr and 360Bhp and reliabilty........ No

Litchfeild T25's have proven their reliablablity over the last 4+ years. They used their own designed pistons (Forge) but now use Cosworth built 2.5 engines and Pistons. IIRC AFAICR

Happy modding

Tony

white

UK STI mate.

I know that mate, I just wasn't sure as to whether they ran the same material pistons or not

Personally I think that the 340 package will be more than fast enough for me and is probably reaching the maximum level as to on the road power IMO. So in your opinion, the standard internals will definately be OK on the 340BHP level?? Out of interest, do you think I would be looking at silly money to have forged pistons installed??

Yep, the next T25 sounds interesting. Cosworth prepared engines running circa 400BHP

ex-webby

Who told you that?

I think PowerStation and Prodrive will be able to tell you something different with all the testing they have done on the 2.5.

From my understanding the hyperheuetic pistons are very brittle and prone to failures around vibration (ring lands etc) from high boost levels...... obviously though at the level discussed on this thread this is not an issue.

If I was to crack my block open I would be putting Forged pistons back IN!

Regards,
Shaun.

white

Anybody got an idea on what sort of price I'd be looking at to have forged pistons fitted, including parts and labour??

£1.5K-£2K would be the ball park I'd imagine

TonyBurns

iTrader: (3)

Like i said, they are more susceptable (sp) to det but they are strong in the direction they need to be, ie straight though a "proper" forged piston would be better, not what subaru call forged

Tony

TonyBurns

iTrader: (3)

It seems that a lot of the MY05/06 JDM 2ltr STi's are pushing out 330/340 out of the box, thats saying something about reliability on those pistons
Remember the S203/204 use the same engine with 320ps out of the box over the 280ps of the other cars and if a 280ps car is pushing 330bhp.....

Tony

T5NYW

iTrader: (4)

I think it's more a case of Piston size and not material, 2.0ltr is a fair bit smaller


Very just need to related to someone named Pirelli or Bridgestone

Personally if I had a UK car would stick with PPP and full warranty. althought I highly rate PS and Mr Litchfield my car is a real Hoot now

Tony

T5NYW

iTrader: (4)

Yep y MY06 (2.0ltr) easily made 349.9bhp with sports Cat and a tweak

Tony

hades

Under the way the EU law works, you invalidate your Subaru warranty relating specifically to the parts effected - this is in this case likely to be the engine, gearbox and rest of the drivetrain (which I admit is a very significant proportion!) Interior electrics, bodyshell etc should definitely still be covered on warranty (even if Subaru UK object initially). Brakes and suspension is a bit of a grey area as they are clearly gonig to be a little bit effected, but many failures shouldn't be attributable to a power hike.

I've seen an awful lot of variations on hyperheueretic etc - any definitive answer as to what is the correct spelling?

ricardo

hypereutectic

See: http://en.wikipedia.org/wiki/Hypereutectic_piston