I own a 1986 Porsche 911 Carrera and early on worked as a Porsche Tech for 10 years. Porsche used Rotella T as the factory fill on new cars for many years. In visiting the PCA website the tech for PCA still likes Rotella and uses it in his shop.
As Chris states below, the ZDDP numbers are going down and Diesel oil may be the best offering at the local parts store.
I use Rotella T synthetic 5-40 in my Porsche with excellent results.
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I hate to open up the oil discussions again, but I am getting ready to do an oil change before winter. I was prepared to use my usual Mobil 1 0W-40. I've been reading about the new SM rating and the lower amount of the ZDDP additive. This is supposed to have an adverse affect on our solid lifters. I've seen all kinds of recommendations, usually oils for motorcycles or Diesel engines. I've even seen that Mobil has reformulated their Mobil 1 Extended Performance 15W-50 (1200 ppm phosphorus), Mobil 1 0W-40 (1,000 ppm). Porsche seem silent on this issue.
My questions are, what is the minimum level of ZDDP we need? Should I be concerned about this?
As you know, there is raging debate about this. Porsche lists Mobil 1 0W-40 as an approved oil for everything back to 1984. Since you don't have hydraulic lifters, just to be safe you could run the EP. Shell makes a 5W-40 called Helix Ultra that is an SL oil and is approved. For regular oil, find those with a CJ (diesel service) rating, such as Shell Rotella T (Shell recently announced that they have made other chemical adjustments to make up for the lack of ZDDP) or Chevron Del0 400. Other good oils include Swepco 306 and Brad Penn. Additives are another alternative. There is disagreement on the amount of ZDDP that is beneficial, so I'm not going to make a recommendation here, but yes, you should be somewhat concerned.
Chris Powell - PCA WebSite - 10/14/2007
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