radiator cap pressure question

[europower]

I have a question, i see some of my friends cars have different radiator caps, some say 100 some say 120 and most say 140.
What is pressure for w116 with a turbo 617 engine?
What is pressure for a w123 non turbo with a 617 engine?
What is pressure for a w124 with a 603 turbo engine?

Thanks in advance