i must be real unlucky then

AEM wideband, bosch sensor, placed after turbo, before cat.

So it is knocking killed the engine, right?

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MY08 STI 422whp at 1.5bar on E85, built by Diversion Garage, assembled and tuned by EvoR

Update from new owner: 375whp at 1.4bar on 98, at Tokyo Motorsport

Or VERY VERY lean

What were the AFR's like before it popped?

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[CENTER][SIGPIC][/SIGPIC][/CENTER]
[CENTER][COLOR=#ff0000]Built Ej207: Semi-closed RA Cases - Wiseco Forgies - Manley rods - BC 272 cams - GDA Heads - billet f/whl - Vi-pec - WbO2 - 800cc Yellow tops - TD05-20G - 409Hp ath @ 1.75bar on E85[/COLOR][/CENTER]

Catastrophic detonation is not related to fatigue.....You said "I think fatigue is the reason why most old sti has piston failure" - You are not correct in your assumption......Most of them Die from big end bearing failures.

The STI Bug in question failed due to a leap in Volumetric efficiency that the ECU was never designed to compensate for, which probably lead to severe DET.

Detonation is a pressure spike with enough energy to crack cylinder bores, bend conrods & shatter pistons.

Engine Detonation causes a very high, very sharp pressure spike in the combustion chamber but it is of a very short duration.

The sharp spike in pressure creates a massive force in the combustion chamber. It causes the structure of the engine to ring, or resonate, much as if it were hit by a hammer. Resonance, which is characteristic of combustion detonation, occurs at about 6400 Hertz. So the pinging you hear is actually the structure of the engine reacting to the pressure spikes.

The high impact nature of the spike can cause a clean fracture of the ring land, bend conrods and fractured valves-intake or exhaust.

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[CENTER][SIGPIC][/SIGPIC][/CENTER]
[CENTER][COLOR=#ff0000]Built Ej207: Semi-closed RA Cases - Wiseco Forgies - Manley rods - BC 272 cams - GDA Heads - billet f/whl - Vi-pec - WbO2 - 800cc Yellow tops - TD05-20G - 409Hp ath @ 1.75bar on E85[/COLOR][/CENTER]

Show then the log simon?

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The one perkent...

ok here is the torque log. this is the section in which i believe detonation occurred
outside temp was about 34c. intercooler spray was being used. this is after about 1hr of driving with no issues whatsoever


note: in terms of the AFR's, since they are readings from factory o2 sensors and not wideband, how accurate are they?

loggy log

Lol, closed road.

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Air is for pussies.

Look at tve lines around 12:46:21. Thats pretty lean for full boost.

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The one perkent...

I'm sure it had speed when I looked at it 15 minutes ago..? Wise move.

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Air is for pussies.

207 has forged pistons...

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