I want some informed opinions here. I read in the manual that the Z should run just regular mineral 5W30 motor oil. I put 5W30 Castrol full synthetic at 2000 miles (3000 km). I've been told by a reputable source that some cars run better on regular oil versus synthetic due to the "impurity" content in the mineral oil. And before someone out there slams that argument, let it be known that it was made by a stress failure engineer, I'm a chemist and in my opinion (without getting into the details) the argument holds water. But I'd like to know if anyone has asked Nissan what they recommend? My dealer says mineral oil, has anyone else heard different?

 

As far as the Z is concerned I don't know. I'm just in the process of ording one right now. I can tell you from my pasty experience with other cars though. I had a bmw 325xi which came factory with synthetic. The synthetic with a good filter is excellent for high rpm, high compression engines and lasts quite a long time though you do take a hit as far as cost is concerned.

It is true that some engines run better on natural oil. Synthetic has finer molecules. The natural oil has a tendency to "fill in" areas that the synthetic would not such as old seals. This is why it is a bad idea to put synthetic in an old engine that's run natural oil it's entire life. I also have a dodge durango and would never dream of wasting synthetic in the beast. I guess a number of people have tried it and have seen increased oil consumption and some even claim decreased performance.

Hope that helps a little.

 

Thanks that does. I've also noticed that my oil pressure at higher RPM is a little lower with synthetic.