I use RaceChrono on my phone in landscape mode, and I also use it on the head unit in my car via Android Auto.
It works great when I'm only looking at data graphs in the Analysis mode, but when I open the map both halves of the screen are too short.
What's even worse is that one of the local AutoX locations is longer North-to-South than West-to-East, so I have to choose between a squished overview or cropped zoomed-in view.
Here's an example: https://imgur.com/hdRgF8S
Also it seems that the zoom level gets reset whenever I leave and reenter the Analysis mode.
I wonder if you've considered:
a) allowing the user to switch between horizontal splits and vertical splits
b) allowing the user to drag where the split is (i.e. instead of just 1:1 ratio it could also be 3:1, 2:1, 1:2 and 1:3?)
c) saving the map parameters, such as the zoom level.