ConfusedGarage

Let me start by saying this car was used hard and made big power numbers, nobody is crying foul here. We never thought the car was going to last 300,000 miles at this level and heavy duty cycle use - but wondering if repaired with better cooling next one would last longer.

Here's the scoop: Friend of mine lost a piston (can't remember which) in his LS9 the other night just when he went into 5th gear on a test run. Right when he hit 5th the car lost power and he saw some smoke out back. Once parked modest amounts of oil dripped out of the exhaust. Broken piston was found upon teardown. I'm wondering if a lack of cooling mods played into this given his use and power levels??

Car had 22,000 miles as of kaboom, 6 track days (these were long private rentals to ourselves - probably more like 8 track days when counting by track hrs) and a couple drag days but no more than a couple dozen passes total. Additionally he did 4-5 "mile runs" at the airport while at 640rwhp level. Was stock first 10,000 miles, then was around 640 with the basic bolt ons until around 18,000 miles. Last 4,000 miles car made 803rwhp on meth. Even the street miles were pretty hard use, he does not baby this thing.

I believe it had an upgraded heat exchanger, and maybe bricks, but the radiator was stock as was the rest of the cooling system. The car had gotten hot at a couple of different track events where I worried the rings were starting to fry, but clearly there was a bigger loss than just rings.

I wonder if something like a D3 cooling setup had been on this if it would have lasted longer. I don't have details on what the one broken piston looks like, nor do I have that on the others. I will add info when we know as that could help determine what caused this beside the obvious hard use and power level. Again, nobody expected this to last forever given the use and power, but honestly I think if the car was properly cooled when modded it would have lasted another couple of seasons. Maybe not.

Will add more detail when we know more details on the internals.

Forgot to add - the heads were addressed previously and perfectly intact when removed.

lt1z

meth failure?

ConfusedGarage

Possibly, I wouldn't rule that out. Should know more soon after the holiday weekend.

mirage2991

Ring butted and broke the piston ring land. That's my guess. Especially at that power level, and if you said the car was running hotter than designed, this could put a lot more heat in the rings.
I wouldn't dismiss the other ideas like meth failure, injector issue in that one cylinder (maybe it went lean and detonated).

whatcop?

Agreed with this one. Sounds like a heavily meth dependent car and the meth failed and she went very lean and took the piston out.

Hib Halverson

LS9 making 200-hp over stock at the flywheel? Plenty combusion heat there.

Yeah...I'd guess a ring butting or the that cylinder was in detonation.

Seven11

What was METH used for?

for cooling the AIT's?

or for additional fueling, to run higher boost and higher timing advance?

Running meth as a fuel supplement is not a good idea. Unless you run a standalone ECU, it will have a secondary controller for meth flow, not ECU itself controlling it, then any failure in the meth flow will have terrible results. ECU does not see any problems and doesn't react in time to save the motor. Even if it doesn't completely fail, you constantly have to log and see if everything is ok.

Meth is good for keeping AIT's in check, worse that will happen is the engine will retard the timing and pull power. Better than a new motor.

Running a proper fuel system is the way to go. Either get one that will run E85, if you have access to an E85 pump or run race gas but it's much more expensive per gallon.