I finally found the NYCity taxicab oil test. This makes interesting reading and debunks many myths about motor oil.
Hope it helps you folks here on the site.
The first report is from Consumer Reports, not Consumer Guide, as I had thought.
Its web address is.
http://www.moneybluebook.com/article....oilchange.php
Not sure why the link above is not working, seems the address is edited when I post.
This is how it should read, after the thee w's
moneybluebook.com articles consumerreports.oil change.php
add a backslash between the single words. moneybluebook and consumerreports are spelled out as one word.
The second report, but it looks like Amsoil attempted to copy the first report, is.
http://www.pecuniary.com/synthetics/.../taxitest.html
Good info, even if you don't agree with everything in the reports.