Hi all, I did a search, and could not find anything that may of answered my question, so sorry if it had been asked before. With the TBN rating of an oil, is there much difference in say a 10.5 to an oil that is 7.9? I'm asking because an oil I was currently using was 10.5, but now is only 7.9. And I want to know if this is reason enough to have a look elsewhere? I originally chose the oil because it out of all the ones I looked at had a high TBN, so I thought it would have a great detergency package. In petrol engines, would there be much noticeable difference in using a TBN of 10.5 as to one that is only 7.9? Also, I found out the oil doesn't use any Boron! A bit of Molly and a good amount of Zinc, but no Boron. It does however have near 3000ppm of calcium, but they have lowed the TBN to 7.9! Am I worrying over nothing?