Originally Posted By: Imp4
Originally Posted By: Virtus_Probi
Valvoline even gives us NOACK loss for their 5W30 AFS, that's pretty unusual in itself.
And we know that this is unusual because of the inherent variability in reported results between test setups when testing the same oil to the ASTM D5800 standard.
So Pennzoil claims.
Maybe Pennzoil doesn't see a marketing advantage and/or has something to hide?
I'm sure every single parameter they measure has noticeable variability between test setups and even for a given setup.
I have noticed that the PQIA will retest NOACK when they get a reading that surprises them (i.e. PYB 10W30) and the first and second results have always ended up being fairly close, although I would guess that is with a single setup.
If the loss that is published is +/-1%, there is still value in the information. If it's +/-5%, it's probably useless for standards to require 10-15% NOACK loss results in the first place...which tells me it is not likely to be anywhere near that loose.