Wanhao Duplicator 4 Fan Duct

I never use my right extruder, so to extend the life of my gantry motors, I removed it (along with the motor) and replaced the whole motor-extruder assembly with these two parts. The fan duct can be installed from the top (recycle the right motor's fan and connect its leads to that of the left motor's fans) and both pillar and duct can be secured by two screws (I used a pair of 60mm M3 hex screws with nuts and lock-washers).

The nozzle points a solid beam of air straight at the left extruder