Originally Posted By: SonofJoe
The table suggests that Elf Excellium and the Yacco oil claim to be A3/B4 oils. If they met the latest incarnation of ACEA A3/B4, then they should have a TBN of at least 10 like most of the other oils. They don't.
To meet the older version of A3/B4 the oil would need to have a TBN of at least 8. My guess is they tested the Elf oil and got a TBN of 7.55, figured this must be wrong, retested and got a result of 8.45. Usually, in an attempt to be 'honest', you'll quote both results rather than dump the original 'wrong' result. Averaging the two results gives you 8 dead so this oil is only just on-grade vs the old version of A3/B4.
I've found some more information on this: the first result is from a russian method not comparable to the correct ASTM procedure, the second result however is comparable.