There is a current limit feature in the ESC parameters. What I have seen in track testing is the car itself limits the current as there is only so much torque you can apply at low speed before you get wheel spin. Once wheel spin is induced motor RPM climbs rapidly and the motor current drops equally as fast so the time spent in the extreme high current region is short.
Regarding chassis damping I assume you are referring to inherent damping in the drivetrain due to bearing friction, drive belts and so on. This effect is partially covered in the model by the drivetrain mechanical efficiency term and a friction term. You are right in that there should be another term related to the RPM of drivetrain components. As you pointed out this is difficult to determine. It could be measured by removing the pinion and getting the car up to speed and then recording the deceleration curve. Subtract out the rolling resistance and aero drag and what’s left is the drivetrain friction and damping.
From what I have seen so far this effect is probably minor in relation to drag and rolling resistance. If you know of any sources for Lift and Drag coefficients for different RC bodies that would be very helpful.
I’ve installed the eagle tree datalogger back in my Losi Type R and will do some testing tomorrow at our club race. The model predicts it should reach a speed of 40 mph at the end of the straight. Max speed is 42 mph. Gearing is 46/118 (43.3 rollout , 4.57:1 final drive ratio), Novak GTB and 10.5SS Pro.