or else

It can be replaced by "or" here. Actually, you don't replace it. You just omit "else". It seems that it can be replaces almost in all contexts but I don't want to make a generalisation.

For the time being, no.

New2grammar

He better tell me where my car is or [else] he'll be beaten to death.

I'm trying to use "or else" but it seems like or else can always be replaced with or. What do you think?

RayH

New2grammar

He better tell me where my car is or [else] he'll be beaten to death.

I'm trying to use "or else" but it seems like or else can always be replaced with or. What do you think?

Actually, when you say "or else" in a context like this you omit the specific details of the threat. So "He better tell me where my car is, or else."
If you include the details of the threat then you are correct that "else" can (perhaps should) usually be omitted.

"He had better tell me where my car is, or else." [It should be 'had better, not just 'better'.  OR He'd better ... (especially in speech)]

"He had better tell me where my car is, or else..."  [(The sentence should end with three dots (ellipsis)]