I’ve downloaded your results and rescaled the data range to see if I could spot any contour magvorticity values and from a scale of 0 to 1000 (arbitrary number as I’m not aware what the maximum vorticity should be) you can see some flow effects.
You will notice that cells near your car are quite large and may not sufficiently fine and this might hinder your analysis of how the vortex generators affect the car as seen in 2. Additional screenshots are below.
In 5 there does seem to be significant vorticity behind the wake of the car so you might want to investigate further. Just ensure you can rescale the data to see some differences in results.