Well said. Definitely hard to decide what I want in an oil. Sure TBN retention sounds good on paper but if it ain't eating up the acid in its effort to retain said TBN for 20,000 miles then the oil ends up being acidic as can be at the end but still TBN leftover. LOL.
Seems the best oil is an oil that is designed for a set interval and it goes to work 100% the entire time and is toast when it's designed to be toast and then you dump it in favor of fresh Lube and additives.
I don't understand what you're saying here. If there is acid entering the oil then it will deplete the TBN.
When you test for the TBN you titrate it using an acid. Either it has neutralizing capability or it doesn't.
Some engines deplete the buffer faster than others since they are depositing more acid per mile into the oil.
Not necessarily. Read Sonofjoe's comment again. Some TBN is better than others in this regard. Like he said, he would choose the oil that has a lower TBN based on the fact it is likely doing its job better.
Another comment on it from another member.
Historically, the characterisation of fresh and used diesel engine lubricants has been based on a limited number of analytical techniques. One of the most important methods of analysis has been total base number (TBN) measurement. Although TBN measurements are informative, easy, and quick, it can be misleading to base the judgement of an oil's performance solely on one criterion.
This paper offers some observations from a field test, showing that some detergent types gave unacceptable performance even though the TBNs were at an acceptable level. It is hypothesised that some detergents do not effectively neutralise all acidic species present in the lubricant, thereby reserving their own base, while in fact the oil may no longer provide sufficient protection against bearing corrosion.
This hypothesis is supported by bench and engine test data. It is recommended that, at a minimum, total acid number (TAN) measurements be included in any analysis
, and where time and cost permit, wear metals content, oxidation, soot content, and viscosity should also be evaluated."