Yesterday I've managed to make some mods to Berta. Maybe not the most spectacular ones but for now they will do
First I've made an upper grill block.
Unfortunately it's behind the actual grill. I want to modify the whole front of Berta, so I don't want to spend too much $$, because I'll destroy it anyway.
It's made of waterproof cloth, supported with styrofoam from the back.
Then I've decided to canalise air flow from lower grill to radiator and most of all to IC. So I started with insulation to stop air from leaking to the sides, top and bottom of radiator and IC, then I've made an air tunnel from the opening of lower grill to IC and partially to radiator. And I've decided to close 1/2 of lower grill for better aerodynamics.
A sheet of plastic cut to the shape of the inlet and wrapped with black power tape.
So for now I have blocked ~4/5 of whole airflow trough upper and lower grill inlets.
Marked in blue