Bambu Lab Hotend Kit for Elegoo Neptune 4

With this kit you'll be able to use a hotend designed for Bambu Lab Printers. Also, thanks to the work of OrzOrzOrz and PapaSchlumpf, your printer will be much quieter.

Update: By now there are so called upgraded hotends for the Neptune 4 that use the same ceramic heater and the same nozzles as the aliexpress hotends for the Bambu Lab printers. I recommend those, as you get the same performance but it's less work to install. So get them and use PapaSchlumpf's or OrzOrzOrz's model.

You will need 3x 5015 fans, 6x M3x20mm screws, 2x M3x6mm screws, 2x M3x16mm screws and 2x M3 nuts. You will also need a 27mm PTFE tube, although you can just shorten the original one. Of course you also need the Bambu hotend, I got a 3rd party one with replaceable high flow nozzles.

The thermistor of the Neptune 4 and 4 Pro will not fit into the Bambu hotend, so you will have to crimp the Bambu thermistor to the Elegoo plug.
The ceramic heater of the Bambu hotend is plug and play.

You will need to change the fan plugs to JST ZH 1.5mm. Note that the polarity of Fan1 (the front Heatbreak fan) is reversed.

You can reduce the fan speed of the Heatbreak fan in the Klipper config, I reduced it to 0.5.

Before installing, increase your Z-Offset to make sure the nozzle does not hit the print bed. 
After installation just run PROBE_CALIBRATE if you're running OpenNept4une (which I highly recommend) and you're good to go and can fine-tune your z-offset and calibrate everything else for your new hotend. 

If you're running stock firmware, make sure you set your z-offset with the touchscreen, or set it to 0.0mm with the touchscreen, reboot, and now only set it with Fluidd. If you go this route, you can also run PROBE_CALIBRATE and fine tune your z-offset with Klipper.