Awesome info there dlr. :tu
Not that my personal experience will help this at all, but I'll share it anyway. I use to make trips to Atlanta at least once a month, when my parents lived there, so I would spends hours on the interstate. To entertain myself I would sometimes find a willing individual that would allow me to draft off them, or vice versa. On one occasion I was behind an 18 wheeler running 90-95mph. I was in a very low Toyota pickup, with aftermarket airdam, but I also had a bug guard on the hood. The suction from the truck was literally pulling me along, and the bug guard would actually blow forward, all the while running at only part throttle. I was dangerously close to this truck while doing this, but it was cool to see the effects of drafting. On another occasion, I drafted with a guy in a Maxima for two hours running 100+mph. Definitely not as noticeable of a pull coming off the car, compared to the truck. Fortunately never got a ticket or in a wreck, and people around Atlanta are freaking insane on the highway.