opinion on oil

ImportConvert

A few years ago I actually read a post on BITOG where they tested a car, taking samples of the oil as the miles racked up. There was less wear metals, proportionate, with 3K miles on the oil than when the oil had just gone in. It seemed the oil was protecting better the older it got.

As long as your TBN's are holding up, and the oil is good and stable, you are G2G. If your oil hasn't sheared down and the TBN is still effective at 9K miles, go for 10. I know a guy (PATMAN) on the old LS1 forums that did TONS of UOA work, and he ran his 'vette for 9K between changes with 0-30GC, and Blackstone told him it had more in it.

ETA: Just found this backing up what I just said:
http://www.dtsc.ca.gov/TechnologyDev...il-Filters.cfm

I'm not really a "save the planet" type, but if I can reduce the amount of waste I produce while saving money without harming anything, I think it's a plus.

All this being said, the 370Z does tend to run a bit warmer than many other engines do. It would do you good to send off a few UOA's to see how your oil is holding up, especially if you use some of the more unstable oils like Mobile 1 5-30, etc. (yes, that is a back-handed swipe at M1).