Originally Posted by UnleashedBeast
I have found some of the answer, but I think I also found a mistype.
Here is a quote taken from a thread on BITOG about low NOACK for Pennzoil Ultra 5W-20 SN
250*C is 482*F, beyond the flash and fire point of the lubricant. It would burn, no way they are testing NOACK at that temperature. Most likely, they are testing at 250*F. In that case, Amsoil tests at 302*C (150*C).
More tests comparing apples to oranges.
In the past six months, I have been told by those at Amsoil corporate that a new GTL (Gas To Liquid) process was about to be the new best base stock for a formulation. Let's wait and see who else jumps on the bandwagon with their best formulations.
Astm D5800 is a standard industry test using a flask heated to 250 degrees Centigrade. So Pennzoil, Amsoil, etc are held to the same standard. Pennzoil Ultra is, by most accounts, using considerable GTL base stocks. I'm not saying it is necessarily as good as or better than Amsoil, just that it's a really good oil for the price and may be a good solution for direct injected engines.
Incidentally, I sent an email to Pennzoil today asking about the PDS confusion and was quickly sent the SN version that shows volatility in the 5% range.