Originally Posted by Garak
Originally Posted by Imp4
It's a notably variable test, that is demonstrably non-repeatable from test rig to test rig.
I suspect that, and perhaps base stock interchangeability, as the reasons to not report it overly publicly. They show one result and PQIA shows another (although they're apparently not doing it now, either) and then you have a mess. When PYB showed a much lower Noack than reported, everyone was happy. If it were reversed, but still within specs, email boxes would overflow with BITOG outrage.
GumbyJarvis: I'm not sure. All the companies seem to release some and withhold others. I don't think it's something pernicious, just a legacy of different people overseeing data sheets over different periods. Heck, look at what Patman mentioned. Sometimes, all it matters is who answers the email or the telephone. One person will act like you're asking for the recipe, another will be confused, and then next will hand the information out.
Good points. They all seem to want some wiggle room.
Culled from Pennzoil Q&As dated 05/20/18...
API SN Plus & 0W16 Q%A
12. NOACK is not declared because of the "inherent variability of the test."
Same goes for HTHS from a couple of questions later.
