What is the best synthetic oil?

Originally Posted by WarmAndSCSI

Mean wear is definitely useful; but most people tend to focus on the outliers (results from cars that are beat the hell out of, cars that are babied beyond all reason), which is just illogical.

Castrol Syntec is excellent stuff - 0W-30 is unbeatable for the price (~$7/qt). Pennzoil Platinum is a favorite of many and its real-world performance and specs on paper back it up - it's as good as Mobil 1 but generally cheaper.

Pennzoil and Quaker State are basically made from the same stock now since Shell owns them both. Shell Rotella, Pennzoil, Quaker State - all good synthetics, all made by Shell's SOPUS group.

I've never used Pennzoil Platinum, and never paid attention to when I used Quaker State Q or Horsepower of whatever the hell it was/is called.

You can pick up German Castrol at Auto Zone. It's been separate from the other Castrol oil every place I've been, and they usually have 5-10 quarts in stock. Make sure it says European Formula on the front and Made in Germany, only for sale in the Americas on the back. There are some unknown batches of US-made 0W-30 (circa 2002) still floating around, and those are to be avoided since they may very well be Group III-based and heavily packed with friction modifiers (much like some other cheaper 0W oils).

Mobil 1 0W-40 is also tip-top oil and can be used with our engines since it's essentially the same viscosity at every single temperature as Castrol Syntec 0W-30 is. Castrol 0W-30 is a "thick" 30 wt whereas Mobil 1 0W-40 is a "thin" 40 wt. They're roughly equals.

I'm digging German Castrol on the Z so far - dropped oil temperature 5-10 degrees from the stock average cruising temperature. Idle noise is the same as well, if not quieter.