I'm struggling to get my printer to the temps required for modified PETG (the filament I have is Fillamentum CPE and recommends 255-275 °C), I currently can only reach 245/250 °C even if my target temperature is above that. The hot-end is fully ceramic wrapped and metal (no PTFE liner to worry about) and the printer is in a DIY heat shielded enclosure (non-heated).
The printer is an old (but gold) Wanhao Duplicator 4 (Rep 1 clone) with a MK8/9 extruder running a custom build of Sailfish. I know there is a firmware cap at 280 °C but that's fine, I don't intend to go above that.
Bar totally swapping out the extruder assembly what can I do to up the hot-end temperature, upgrade the power supply, heater cartridge?