I was messing around one day, removed hood and did some burnouts with Grand Marshal, I could not see torque twist, engine is not moving at all. Also I don't see car bodies moving when revving engine on neutral, which happens with big V8 in reality. With big T-Series, I don't see one or two front wheels lifting up into air, when having big load and pulling to very steep hill or lauching from stand still, which is what happens in reality, even on dirt roads front wheels can lift up. I have had around 3000Nm torque in T-series and more than enough weight. Drag cars etc. show that effect also. So torque does not put twist to engine and from there to frame in same manner as it does in reality, however I see torque reaction nodes, which bring me to question if there is something currently not yet implemented in torque reaction nodes and how powerline delivers torque? I'm not sure, but it might have little something to do how cars grip during acceleration too. Some clips for purely scientific research purposes:
Currently we resolve the primary reaction torque from the wheels in braking and driving (ie brake and axle shaft torque), but not the secondary ones from driveshafts or the engine rotating inertia. Mathematically we have the tools to do it but given the complexity of the powertrain system, we have to work on a sane way to integrate it all.
Sounds to me that there are interesting tasks coming to you with development, I will follow with interest of this evolution you guys create
I'm not sure exactly but until perhaps early last year, the engine torque reaction nodes were used, but the math was incorrect, causing the car to spin around in 0g, so we removed those engine forces and focused on the wheel reactions only. Currently the torque reaction nodes don't get any forces applied, but they are used for some minor things like sound, positioning in the powertrain app. We will probably reuse them in the future to create the reaction from accelerating the engine inertia.
