just wondering what "normal" cruising and max egt numbers would be for an aaz? i seem to remember one guy was running 1500ish deg for short periods before bad things started happenin.
With a VNT on mine, the vanes were looking pitted and slightly melted from long runs at 1400, though I don't know how much was also from piston pieces finding their way in. The valves didn't look bad however, so I think the turbo is the main factor. Although there is the question about why the piston broke. It could be that the head was hot enough that the pre-chamber became loose and hit it, or maybe just piston slop from the sandblasted bores allowed the piston to start hitting and loosening it. I try to stay under 1300 now though, even though it's a TDI with no pre-chambers.
My AAZ has:
- blocked wastegate
- heavily modified pump
- standard exhaust except for a mysteriously empty cat
- no intercooler
and I run between 800-900F on the highway at 65 mph. Short bursts to 1500+ (ie both boost and EGT needles buried) for passing, scaring myself, etc, with no problems so far, but I consider 1300 to be as far as I'd want to hold things for anything more than a short burst.
The Air Spruce EGT probe is so responsive you can see how quickly things heat up and then cool down... so I'm never way in the red zone for more than 10 seconds or so.