Development of the Sequence VIB dynamometer engine test procedure for evaluating the fuel efficiency benefits of engine oils has recently been completed. This test was designed as an improvement over its predecessor, the Sequence VIA test. It evaluates fuel economy using a range of boundary/mixed and hydrodynamic lubrication stages selected to better represent a wider range of engines. In addition to determining “fresh oil” fuel economy, the new test determines fuel efficiency retention after a second oil aging stage that corresponds to 6437 - 9674 km (4,000 - 6,000 miles) of pre-certification aging of engine oils in vehicles and is representative of customer use. This paper describes the selection of aging conditions and length.