First, Vehicle Physics Pro DO require being familiar with car tuning. VPP implements a fully realistic vehicle simulation model where the behavior and handling of the car depend of the combination of the setups in each component. If you need a simulation model that doesn't require car tuning knowledge, try Edy's Vehicle Physics instead. In EVP you can set up the acceleration with a couple of parameters.
In VPP, the acceleration of the car is defined these parameters combined:
- Drivetrain: engine power, gearbox ratios, differential ratio.
- Tire friction: how much power they can turn into traction.
- Rolling resistance applied by the wheels.
- Aerodynamic drag applied by the aero component(s).
If there's power enough but the wheels spin easily, then the limiting factor is the traction (tire friction). If there's power and traction enough, then the typical factor that limits the acceleration is the combination of rolling resistance and aerodynamic drag.