Hi, I just did this layer fan venturi to have a bit better flow of air coming in. I have found to have a less noise fan working this way not sure if flow is better.

You just have to print the part from PETG, PLA or ASA, 0.10mm LH. I will need to stick the part to the fan I use E6000 glue. This way I can easily remove the part if a want. Don't use superglue!!!

If someone believe this can be improve or work better please try to mod.

This is just an idea.