Algodoo

...no competitors

0.5x1m
80 kg engine body + 20 spawn boxes
500 hp @ 18000 Nm
max speed 600 rpm
max torque moment 23000 Nm
power/weight ratio 5:1
+ dyno stand - drag lever(+- 160 gegrees) to change torque moment
Free to use
No jet forse, no moment of inertia. Stable
Also look at glued pistons, it's a good way to save weight and increase stability