As far as I know, 43.5psi. Thats the standard for all fuel injectors as far as I know. Being that I know other nipondenso's are tested / rated at that PSI, and being that they are supplied for Toyota by nipondenso, I would assume that they are tested / rated at the same 43.5psi.
Edit: 43.5psi also happens to be 300kPa or 3bars or 3000millibars
