7500 mile oil analysis on 1992 legacy 2.2 turbo engine - 202,500 miles.
oil: Amsoil ATM 10w-30

conditions: rally-x, long distance highway, commute.

TBN: 7.5
viscosity @ 100c: 11.74 cSt

pdf (http://home.comcast.net/~rborlase/pdf/oil.pdf)

Uh, is this good?

yes - they recommended continued use. but it was changed. so maybe I'll go with a 10k interval on the current oil change.

it is a higher TBN (Total Base Number) than other people's analysis.

viscosity for SAE engine oil grade 30 is between 9.3 min cSt and < 12.5 max cSt.
The oil is still in spec for its raiting of 10w30.

My "oil dork" knowledge has gone down, but a TBN of 7.5 is really good for 8000 mile oil. As I recall the oil swap out should occur around 2-3 on the TBN. Thanks for the report, but I really, really like Blackstone's results better as they give you layman's terms and industry averages. This report is for the serious oil dork.

yes, the blackstone reports are more friendly.