You can read this, pretty good information about suspension:
https://www.gtplanet.net/forum/showthread.php?t=202692
I'm still trying to figure out the science behind bottoming out on the road courses, but if your working with a car that's fast enough, (say 180 mph+), you can do a couple laps around Daytona speedway then check the replay. When you bottom out there, it shows sparks