Fuel Economy Characteristics of Motor Oils as Measured in a Consumer Road Test

A 215 car “consumer type” road test was run to investigate the influence of various motor oils on fuel economy. Under “real life” conditions, the differences between conventional 10W-40 oils and several 10W-40 oils formulated for fuel economy were small. Furthermore, such differences would be difficult for the individual consumer to detect as a result of other variables such as changes in driving patterns and the effect of seasonal temperature changes. The methods for adjusting the data to compensate for these factors are explained.