Melting fiberglass

[Blue]

Yeah, and neither should inconel.

The header wrap that melted was Moroso, IIRC, and it is white.  I assume it's fiberglass but maybe not.  When it melted, it left a black glassy residue on the pipe.
That IS fiberglass.  Get the better stuff.  Fiberfrax is really good, Zircar is the best and most expensive;  there are others.  Do not use carbon.  It's not a good insulator, it merely retains its strength at obscene temperatures.  Pitch-based, high modulus carbon is actually a better thermal conductor than copper.

[McRat]

Some of the problem is that the fuel continues to burn after the valve opens.  Diesel burns slow.  Running a bigger A/R on the turbine hsg is something I'm trying next.  But no matter what, it takes big backpressure to make big boost numbers unless you compound chargers.  As far as hotrod diesels go, I'm not pushing much boost, 45-60psi, but since it's a single charger, drive pressure is high.

This is actually an injection and burning issue.  If the fuel doesn't finish burning before about 20 degrees ATDC, the EGT is driven by post-burned fuel and not power.  Check your injectors for proper atomization and possibly upgrade to a high pressure system.  There are also diesel additives that help atomization and increase burn rate under extreme conditions.  Some of these also decrease delay time which is risky, but allows you to go to a higher RPM.

I'm running about 29,000 psi fuel injection pressure, and running lots of timing advance.  But I'm still injecting fuel at 30 deg ATDC.  I think I'm going to increase the injector size so I can drop the duration.  For Bonneville, no fuel other than pump #2 can be used.  I have lots of goodies that can increase cetane rating, but none are legal as far as I know.