I was just trying out some things with the downforce on the BF1. In the wing section of the setup screen, there's a measure of the downforce in N. But I noticed the undertray always gives the same amount of downforce (-9600 N at 100 m/s). But I thought, real F1 cars lowered there cars as much as possible to get as much as possible compressed air under the car, for as much as possible downforce. But in LFS the ride height seems to have no influence on the downforce.

Is this a bug? Or is it still to come in later versions? Or am I just very wrong?

Your right, and its not a bug, it just isn't in there yet. Scawen said he will do the research and implement that later.