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Race within the race

The same team has developed its own multibody dynamic simulation in-house to circumvent a restriction on testing at the tracks visited by the Sprint Cup. “Simulation has been around for quite some time, but in Cup racing it is becoming increasingly widespread,” explained Rex Stump, Hendrick’s top chassis engineer. “It will soon come to the point where simulation is the basis for everything, like it is in F1. It will be total simulation.” Getting accurate simulation, however, relies on getting accurate data in the first place and that’s something the teams cannot do due, once again, to the testing restrictions. This problem is most acute for those who operate the many seven-post rigs used in NASCAR.

“It’s pretty much the same with any simulation program, there’s always going to be a limitation, like here we’re not applying engine torque and braking torque,” said Hendrick engineer Darian Grubb. “We know we are not picking up the lateral forces so we have to work out how to account for that in our simulations, to try to get as close as we can. At the end of the day it’s still

down to the crew chief’s gut feel and the drivers’ feedback of how it’s going at the weekend. Its a pretty hefty task for all the engineers to keep up with all the technology we are pumping at them – we have so many shock graphs, bump-stop graphs and seven-post data. It’s basically information overload.”

But not all that data is based on the best sources, as Hendrick chassis engineer Jon Plyler pointed out. “A lot of the data we are using comes from older data, and we actually have to transfer the drive files and things we created with the old car and try to transfer it to the CoT – the loads, the load profiles, track profile. Then you also have tracks that get resurfaced and change their characteristics. We have to try to simulate but a lot of the time we are not going to have the best data. We have to make the best of what we have. Some teams have tried unlikely methods to get the best data they can about the courses they race on. The big key to what’s out there is the track surface itself, but to laser-scan a track to get that level of detail is cost prohibitive. Then if they resurface the track or the track changes over time, that data is useless.”