I have access to some TGA equipment and while I was doing some work on a project at work I decided to make a crude 200C Nock test and run a couple of tests when no one was using after hours. My test was pretty standard. A TGA basically measures weight change v. temp. so I made a test which held my sample at 200C for 1 hour and then analyized the weight change. The test really ends up being 63 mins as I have about three minutes to get to temp. SO far two tests finished: Royal Purple 10w-30 after one hour left a residue of 66%-so it lost 34% of its mass. Castrol Syntec 10w-30, same test -Residue of 73%, so a loss of mass of 27%. Just a couple of oils I had laying around the garage. I plan on continuing to test a few oils after hours in my pursuit of more oil knowledge, I will post as I get more results.