Did you really only wait like 3 minutes?
Good lord this is precisely what Unity Answers is for, this practically breaks every rule in the book.
before you complain about not having searched around for the hundreds of identical questions, I might as well answer it.
Mass only effects the force in which the rigidbody hits things. You must make this realistic to get the best effect, so >999999 mass won’t work. To do what you are trying to do, you must use Rigidbody.Addforce and it will increase the gravity/weight of the car.
Please…this is extremely immature and very annoying for us Forum browsers.
Please don’t start topics like this. If you have to, you can bump your original topic, but wait a reasonable amount of time (at least a day would be nice).
–Eric