Rostock Max V2 Layer fan shroud large 50mm

The original layer fan of the Rostock Max V2 is a little small in order to really cool down PLA layers. I wanted something better and ordered from 3DWare.ch 3 50mm fans with a 15x20mm large opening. I used a part of the original shroud and added geometry in order to mount the blower fan.
The Rambo board can drive the fans without problems.
I've currently installed one only - and if I use 100% flow, my extruder temperature decreases already from 225°C to 215°C (with the stock hot end) --> I mig