gt37vgt

as i said in the other thread i was told 968 pistons are forged what about S2 ones this doesn't really prove the piston as a weak link considering boost and comp ratio.
also are we all taking it to far with big head studs and fancy head gaskets ??
a blown head gasket is a supermodel menarge a twa compared to that horrer show .
as it was done around max torque i guess it is a overload issue .
there is alot to be said for fail safe boost control .
Thanks sharing Duke its nice to get the lesson with out the experience first hand with that I extend my deepest condolences .

333pg333

I've had 2.5L motors boost to 1.7 - 2.1 bar and drove home to fight another day. Who knows what timing and fuel that was running when it hit 27psi. Wasn't that on cast rods and high compression? Not sure you could blame the piston in this case, not at least without looking at it on the bench.

Raceboy

Duke's engine had reduced compression ration, not 968 stock one.

When it was at max torque it's possible that detonation ocurred, then it makes more sense.

porshhhh951

That would be in line with my thinking as well.

I overboosted I believe(difficult to say because I wasn't watching the gauge at the time and wasn't running logging equipment) and recieved a lean condition myself with caused me to burn a valve(a pee sized whole through it actually)

Duke

Yes it's possible it detonated. But that's one of the many pros with a standalone, the timing/fuelling was retarded/increased for that boost level so IF it detonated it was lightly.
I still think it was the power that killed the piston. 27 psi on that engine configuration is simply too much torque for that piston to take, detonation or no detonation.

Also, take into account that these pistons had seen 500 rwhp for some time before...metal fatigue...

333pg333

How's the cylinder walls Duke?

Duke

In that specific cylinder - shattered LOL...
The block also cracked in several places in the "outmost" material so to speak.