[oil pan 4]

For 1/4 miles time each pound of rotating mass you remove is said to be like removing up to 8 pounds of more static mass.

Since the EPA claims that every 100 pounds of weight reduction improves fuel economy by a few percent you would have to think that the same would be true for rotating mass. It would be very effective (1lb rotating = 8lb static) in stop and go driving but would act more like static weight reduction when the vehile speed remains static such as when traveling at highway speeds.