According to Mark Hughes, Merc's German GP update is supposed to be worth 0.5s/lap (according to the wind tunnel).
They haven't been able to find the right setup for it yet due to the unusual running at Hockenheim (huge temperature swings, compromised setup for inclement weather, switching back and forth with different rear bodywork, etc.)
"The loadings tell us that the upgrade has worked but in terms of how we fully exploit that and what effect the surface had, we don’t know yet,” surmised team boss Toto Wolff.
https://www.motorsportmagazine.com/opin ... s-meltdown
Somebody earlier in the thread had asked about the purpose of eliminating some of the width from the uppermost wing flaps. All about outwash More on the upgrade from Hughes and Giorgio Piola:
"This creation of space between the rearmost [front wing] element and the front wheel will have the effect of enhancing the outwash of airflow around the wheel, moving away slightly from the extreme that Merc’s original full-depth wing represented. A small detail change can be seen in a new cut-out slot at the back of the endplate’s foot section and this is likely creating a small vortex that enhances the outwash effect of the new element arrangement."
The sidepods were also reshaped, something that I don't think any of us noticed this time around.
"The sidepods have been subtly reshaped to give slightly bigger radiator inlets. They now extend outwards, with a slight outward angle as viewed from above, so as to give a greater air capture. Mercedes realised as early as winter testing that the cooling capacity was not as great as had been hoped and had spent some time trying to speed up the throughput of air to compensate before it became apparent that there was no alternative but to increase the radiator size."
https://www.formula1.com/en/latest/arti ... 3AW4x.html