I added some code to the arcadeCar demo for the Newton Game Physics. Ventilator made the demo.
You basically have to adjust torque and max_speed - at least that's what I did to facilitate "tap brakes", "regular brakes" and more realistic acceleraton features. Take a look at it from the link below - it may answer some of your question. Funny, but I was just thinking today of doing something similar and making an Indy car model. If you code it, I would try something like using a keypress to simulate gears, and for each gear establish a minimum/maximum torque and a speed range.
The code I changed is pasted in the thread:
car physics thread Regards, Ron