I'm working with the 1.53 version as wrapped in the TV3D SDK to create a bit of a driving game. So far I've been able to create a fairly stable vehicle setup, with an automatic gearbox and torque calculation using an engine torque curve.
The problem is, I can't seem to get a grip (haha) on acceleration. Even though the vehicle I'm testing weighs 9500 kg (bus) it still manages to accelerate up to a top speed of 90 km/h in just a few seconds, whereas in real life that should take more like half a minute or so. I'm applying a torque to the rear wheels caIculated from the wheel rpm->gearbox rpm->engine rpm->torque curve lookup. I'm also applying a drag force according to the speed as well (dragCoef * v²)
So, can anyone tell me if my values/calculations are wrong and/or how to get a more realistic acceleration
Some settings/values I'm using:
Vehicle weight: 9500 kg
Vehicle size: 12x2.55x2.5m
Engine max torque: 1120Nm @ 1100rpm (diesel engine, so should have a relatively flat torque curve right)
Engine RPM range: ~400-2300rpm (engine RPM calculated from wheel omega)
Gearbox ratios: 3.43, 2.01, 1.42, 1, 0.83 (1-5)
Differential ratio: 5.785
Maximum output torque: 16667.8Nm (assuming 75% gearbox eff.)
Wheels: 2 driven wheels rear/2 steering wheels front
Wheel width: 0.356 (front) 0.856m (rear)
Wheel radius: 0.5m
Wheel weight: 50
Physics settings:
Body Linear Damping: 0.02
Body Angular Damping: 0.75, 0.75, 0.75
Body Inertia: 118947, 119147, 10095
MaxSideslipSpeed = 0.05
SideSlipCoeficient = 0.1
MaxLongitunalSlideSpeed = 0.00
LongitudinalSlideCoeficient = 0.00
Physics materials:
MaterialInteractionFriction(Bus, Terrain, 0.8f, 0.5f)
MaterialInteractionBounciness(Bus, Terrain, 1000f)
MaterialInteractionSoftness(Bus, Terrain, 1000f)