Detonation in that cylinder, look at all the pitting on the piston dome. probably cracked a ring land and it was burning oil. When you burn oil with your gas you end up with very little octane, which would cause the cylinder to start to run super hot and melt.
Check your knock correction range, if it was around the stock setting of 6100 and you were revving to say 6800-7k that's about 1k rpms of no knock control, so it would not pull any ignition, or show a knock count. Not to mention it would be in the range were the td04 is pushing some seriously hot air which would tend to detonate a lot.
What was your timing and wideband AFR.. Hopefully you had a wideband or were tuned with one at least.
Originally Posted by yaya20
Looks somewhat familiar... I'd start by getting your injectors checked out. Looks like cylinder 3???
Here is mine:
Lots of timing or very lean tune or both.. Look at your number 1 piston as well.. Corner nice and shinny. Your EGTs were probably pretty high when that melted. If it was a bad injector only 1 piston would look like it took some serious heat.