The Feb 2025 Blackstone newsletter said this today---FYI:
Blackstone moving away from TBN testing
- Thread starter grumpyoldman
- Start date
Finally. They're also correct about TAN. GM and others have said this for a while now. LSJ did as well. Loading up your oil with a lot of Ca/Mg doesn't automatically make it good. Big misconception.
Here is a great example:
RL 7,500
Notice TAN>TBN. If you were to measure the pH it would be acidic which isn't good.
OA says 65% depletion of TBN & x1 baseline of TAN are considered "Normal". Depending on what the VOA test shows for that RL would say whether it's toast or not. Which as you well know makes it all that more important to get a baseline VOA on whatever oil you plan to run. I think it's great that they are going to run BOTH BN & AN for the same $10 which would give a better picture.
EDIT: It sounds like AN or BN is an option but both will be $10 each?
How long does Blackstone take once they receive your sample, usually?
Searched intarwebz. Says usually three weeks but could be up to six weeks.