I've scale it down to ~1.5m tune density to ~300kg and get about 400Nm of torque on 300RPM, that's pretty good! Not enough for real-weight truck but still good.
"wind" affect geom proportional to airFrictionMult. In that code result always 0 so no air friction for boxes. You cn change it by simple edit code and replace 0 to 1 in the end.