Total Base Number
Total Base Number (TBN) is the measurement of a lubricant’s reserve alkalinity. The higher a motor oil’s TBN, the more effective it is in handling contaminants and reducing the corrosive effects of acids for an extended period of time. As shown in the graph, AMSOIL 5W-30 Synthetic Motor Oil has a higher TBN than Mobil 1 SuperSyn 5W-30 Motor Oil. |