It's hard to diagnose by looking at a video and reading description. Physics problems are always tricky. Here's a general rule of thumb: Scale matters. And I noticed you have a loooooong ass tunnel there. For testing purposes, see if you can break physics in a small tunnel, one that doesn't exceed the dimensions of the cars by too much. If the car is 1 unit of length, make the tunnel 10 units. Then ram the walls and all that stuff. Then you increase the tunnel a little more and repeat the experiment. If it does get worse with the size you probably need to rethink how you are making this tunnel. I suggest making it several sections connected together, so that way the objects are never colliding with absurdly larger colliders.
I don't like writing 'answers' that are not definitive but just suggest something to do, but as I said physics bugs are tricky. You could also experiment with collision type on your rigidbodies.
↧