Algodoo

Two things: use springs with legacyMode 0 and adjust them to make them stronger using damping -1 or -0.5; and make a totally different gearbox. Those gearboxes are obviously not gonna work, because the strenght the car needs is higher than the accuracy of the sim. so if your gearbox didn't have loss of torque, then the circle would probably pop out of the housing. Try to make a gearbox like I do: use two circles that change radius, and those two circles are hinged to the back. those two circles are always overlapping a little, and they stay in the same place, but they change radius. use friction +inf, restitution 0 and lots of density (usually 50 kg of MASS is right)

Also for the springs that connect the flywheels with the circle-pistons, use constant 1e10 (write it), damping +inf, and go tothe script menu, find forceDirectSolver, and put True

thanks again!
now I understand why most people don't build these kind of gearboxes that much

what does legacyMode and forceDirectSolver do by the way? I only know if an axle's legacymode is 0 prevent it from wobbling when rolling too fast

That's hard to explain, but i'll do my best anyways
In earlier versions of Algodoo (and in Phun also) the axles were calculated in other way ("the old solver"), so the axles wete stiffer but resisted very high speeds (more than 200 rad/s at 100 Hz), and the springs worked different (they could have more constant but had some glitches i think). So when the open beta 1.9 came out, Algoryx added a new solver that does the calculations in a separate process or whatever, and for axles,they are MUCH stronger but they get wobbly upon 116 rad/s.

And forceDirectSolver is because legacyMode defines which is the highest solver to use, I think (springs have 4 if I recall correctly) and Direct Solver (the new but buggiest one) can go to the old solver if it finds bugs. so for the spring, if you put +inf damping and 1e10 constant it thinks it's a bug and goes to the old solver, and they become stiff and explode even

Anyways I've never questioned that much, I just use it xD

thanks for explaining for me!