There are some accounts about a tyrant called Pythagoras, who seems to be at the same period of the philosopher, but in cities so far away from Croton and Sybaris (in Western Sicily, concretely the cities of Eryx, Segesta, Selinus and Heraclea Minoa) that I am not sure if it is feasible to be the same. I hope it is though.
Are you talking about Pythagoras the tyrant of Ephesus, as known from FGrH 268 F 3 (likely a synopsis of the passage on this particular individual in Baton's Περὶ τῶν ἐν ᾽Εφέσωι τυράννων, as known from Athenaeus)? There's no reason to suspect that the tyrant of Ephesus has anything to do with the philosopher. None of our texts mentions such a connection. Pythagoras is hardly an unusual name. The New Pauly records some eight important individuals bearing the name, and if you consulted the full Pauly-Wissowa you'd likely get twice that if not more