Algodoo

- Now have a more powerful PC, means I can ram up the simulation frequency and overclock the heck out of my spring engines.
This one still proves to be the most powerful; so powerful, in fact, that I can't make it stall.
Able to get this thing up to 114 ms/s, and it can actually get up the giant hill on my Boop Course in 4th gear.

Same Boxer spring engine car I uploaded a couple months back, but with a gear box.
(Incidentally, I made this modification on the same day as the gearless one, just didn't upload it).

To start the engine, first engage the torque brake on V; this will force it into the ground, and stop it flipping around when you activate the Starter, on Q.
Hold Q until the engine gets going, then disengage the torque brake.
To stop the engine, press A.

Gears are on 1, 2, 3, & 4, and on Toggle.
Press F to engage the clutch.
Press S to engage the brakes.