OVERKILL
$100 Site Donor 2021
I think it's more the massive reduction in sulphur in fuels has reduced the requirement for huge TBN's.Isn't the virgin TBN pretty well worthless on most lubricants now, since they may contain non metallic additives that neutralize the relatively weak acids that come from today's ultra low sulfur fuels, while the standard method of calculating TBN test mostly just looks at the metallic additives.