You either need to recalibrate for altitude or get your LCD checked out.

I'm not worried about it. I log boost from the JDM map sensor and use the ZT-2 as a quick reference as needed.

Holy crap!

Well, really it will depend on what damage was actually caused. The head and cylinder block, more then likely, will need to be re-surfaced. If he was detonating bad enough, he may have cracked a piston, the pictures are not very clear, which will require cylinder wall honing at the very least, if not boring .20 over (correct me if I'm wrong, I can not really see the damage). When it comes to all that, he can either get the block bored and get .20 pistons, or order a new block from the factory, which will be a $$$ bundle. If the head gasket is all that popped, and he shut the car down immediately, then he'll probably just need to get the head machined and a new gasket. But from the looks of the gasket, it looks pretty bad.

Jerry

mitsulogger only works to 25psi ...fact. I back up my logs with more detailed logs from the ZT2 datalog software.

Where was his failsafe with all those big boy mods?

... live and learn I guess.

imagine if it was the aluminum head of the 4b11T of the evoX

Head lifting is ALWAYS a result of detonation. Saying there is no signs of detonation just shows you dont know how to tell. You have to look at side of pistons above the top ring land on the intake side. That is where it starts. The aluminum will be clean and pitted in that spot. Kinda like it was glass beaded. That would be where the tiny alloy specs you would see on your plugs come from. if you were reading plugs.

+^Good info.^+

It would probably be about the same as the aluminum head of the 4g63T.

I'd agree with "usually", but ALWAYS? That's stretching it (pun intended).

you can see that carbon was knocked off the pistons, so there is a sign of detontaion.

if the engine is detonating really bad, you can easily see +30-40 bar of cylinder pressure = lifting head.

Absolutely.

If he ran the same boost and tune with ARP headstuds, he might be purchacing a short block instead. Somethings got to give

Sorry, but got a good question: Mixmastermatt, explain some details about the pull that spiked to 35 psi, like gear, duration, start/peak rpm reached.

You have a log of this event, would be nice?

I do not have logs from when it happened, I only log the car when I am tuning. Outside temp as 37degF. Car had been running for 20-30 minutes, 3rd gear starting around 3k rpm, WOT, freeze plug blew out around 4500 rpm or so, peak hold on ZT-2 displayed 33.1psi. Car was tuned less than 2 weeks ago with 1-2 counts of knock after several consecutive 4th gear pulls on the dyno. Oil was changed before the tune and had no signs of coolant. Plugs were changed as well and looked good. There is no pitting on the piston tops, valves or cylinder walls indicating sustained detonation. The piston closest to the cam gears where the gasket popped was steam cleaned when the gasket blew which is why it looks the way it does. The master auto tech that works at the shop with me even said he saw no signs of detonation.

If the only way to stretch the stock head bolts is from detonation, then why buy ARP hardware? Why not just run high boost with a very very conservative tune?

The "experts" here can believe what they want. I know that I wasn't detonating and that the gasket let go from running 30psi for the last 15k miles on the stock head bolts.


Now, for the car, I'm pulling the engine later this week and putting the rolling chassis in storage for the winter. The engine will be receiving a 2.3l stroker, race prepped head and HTA35r turbo kit. Then everything will be going back in when I get back from Africa at the end of next summer.

I'm no expert, but I do know cylinder pressures during detonation can be an order of magnitude higher than good clean combustion.

Peak cylinder pressure using a good tune will occur at peak torque, right? With that said, the more torque you make, the more cylinder pressure you are running, and the higher strain you are putting on the stock head bolts. And you can stretch stock parts well before you can stretch ARP parts. No one is trying to say the ONLY way to stretch a stock head bolt is through detonation. Peak torque can very well do it also.

So what type of peak torque were you running that night vs. others? That might answer the question of when stock head bolts aren't any good anymore. My opinion is it would be better to talk about stock head bolt capacity in torque instead of boost.