Thanks, Crash, and if others post their actual slips I'll be happy to produce graphs for each of their tuned HP X3s as well.
To take this a step further, I was wondering how a completely different model from BMW's stable would perform in a 'virtual drag race' with our X3 35i stock model at Island Dragway. In order to make it a fair competition it seemed a similarly-powered vehicle with better aerodynamics was out of the question. I also need to stay in the AWD realm, because then I don't have to adjust the equations to account for the percentage of mass on the single traction axle (in xDr cars that number is simply 1 since all mass of the vehicle provides traction to both axles). So I chose the 328i xDr, with 241 HP, Cd of only 0.3, wt of 1631 kg, and frontal surface area of 2.20. This compares to the X3 35i with its 300 HP, Cd of 0.35, wt of 1890 kg, and frontal surface area of 2.63. Dramatically different vehicles across the board. So who would win, and how do these different factors interact to produce the aerodynamic result?
I am attaching some graphs to cover: 1). A 15 second run at 'Virtual' Island Dragway 2). An 88 second virtual Salt Flats run at maximal acceleration covering over 3 miles which illustrates how their vastly different parameters still mesh to produce a nearly identical result. It was especially interesting to see the different velocity phases in which one has the advantage over the other.
I would like to run our X3s against some of the other Mnfrs models as well, but I'm having trouble finding real data for the frontal surface areas of most of them. I'll post a chart to see if anyone knows the numbers, but if not, I can always use the 85% estimate based on height and width.
And if anyone in the NJ and NY area has a friend with a 328i xDr who wishes to join you at your gathering, that would be an interesting race to watch (or at least the models suggest it should be)!
