- Aug 10, 2006
I was at a car rent office yesterday, the owner is a friend and people from ARAL lubes came in to give him an offer for the rental cars of his fleet. I wrote down what the ARAL tecnical manager said about TBN: "TBN, Total Base Number, is based on a sulfonate (such as calcium sulfonate and sodiun sulfonate) that helps neatralize sulfur in fuel. TBN is excellent to combat sulfur but its side effect is leaving a hard carbon deposit on engine parts. Therefore higher TBN oil does not mean it better than lower TBN oil. Each oil is engineered to do a certain job for each type of engine. Normally, TBN for gasoline engine oil is around 5 TBN and 9 TBN for diesel engine oil. Diesel fuel contains a lot more sulfur than gasoline. Some fuel such as bunker fuel contains even more sulfur which required as much as 40 to 60 TBN to neutralize sulfur in it but this 60 TBN oil does not work well in gasoline engine. Even a long life drain oil for new specs (VW, MB,GM) doesnt have a higher TBN then 5-6" Is this true? I thought a high TBN is better for gasoline.