Algodoo

It's good, but I think that:
you should use lenght for the strokes, changing their lenght, and constant as throttle (or if you want it even less laggy, you can make that the constant is fixed, and the spring's lenght is {Scene.my.stroke1 * Scene.my.throttle} and you make scene.my.stroke 1 from 0 to 0.5, for example. You'll get it). You'll have a 1 stroke engine, making it even stronger.

The bore-stroke ratio should be less, so you can rev it faster without changing frequency.

Overall it has enough torque (5500 Nm) and the key starter seems cool. You can't use it in a car, but for a demo engine it's good! It's pretty big also (3.125x0.75 m), but you can use it for a truck or smth else big. 8/10, it's completely usable and looks good!

any idea on how to make the digital and analog speedometer render positive numbers even when going backwards? I know I'll have to use absolute value scripts. Just haven't figured it out

Yes, use this on the object you want to take the values from:
In this case I'll use angVel
Scene.my.angVel = (angVel < 0? (-angVel):(angVel))
Or you can do that with vel(0), it's the same

THANK YOU!!!!!!