Originally Posted By: Bandito440
I don't know much about Porches of that era, although I can certainly appreciate the need for a premium oil in an air-cooled motor. Are you tracking the car or otherwise riding it hard?
Are Mobil 1 15w-50 or Castrol Edge 5w-50 not high performance enough? Would Red Line suffice?
Most importantly, could you share a photo?
The car is sometimes driven quite hard in 90 degree F plus temperatures.
I have been using Mobil 15W50 but was told by a well known and respected Porsche engine builder that the formulation had be changed and that he no longer recommended it. Something to due with reduction of zinc and phosphous.
Not familiar with Red Line or Castrol Edge. I'll check them out.
As for the v twin oil, mentioned by Ramblejam, I am aware of it but it seem it has so much zinc and phosphous that it could damage cats and O2 sensor, just my thinking don't really know.
I'll work on post a couple of photos.