According to Mobil:
[
www.mobiloil.com]
Both 0w40 (the factory fill in modern Porsches and A40 approved) and 10w40 high mileage have exactly the same concentration of ZDDP.
So Porsche is fine with that level of ZDDP.
So this is not just a technical debate, but also a total red herring....
And note i only suggest 10w40 or 15w50 for their higher viscosity when used at higher temperatures (which effectively lowers the viscosity - that's how viscosity curves work...)
That said, both BP and Mobil recommend ZDDP on their websites and provide no indication of dangers, except in catalytic converter equipped cars when oil is consumed above a nominal rate.
Grant
Grant
gee-lenahan-at-gee-mail-dot-com