Future scenarios prepared by Shell anticipate that worldwide energy demand will approximately double by 2050, whilst at the same time, CO2 emissions need to be halved. Therefore, there is great pressure on improving efficiency of all machines, and clearly there is great focus on improving the fuel efficiency of passenger cars. The use of downsized, boosted, gasoline engines, can lead to exceptional fuel economy, and on a well-to-wheels basis, can give similar CO2 emissions to electric vehicles (depending, of course, on how the electricity is generated). A study is reported on a low weight Shell concept car, equipped with a three-cylinder 0.6 litre gasoline engine, which has achieved over 100 miles per imperial gallon, in real world driving conditions. The use of low viscosity synthetic engine and transmission lubricants contributed to this exceptional fuel economy, and data is presented showing how the measured fired friction mean effective pressure (FMEP) of the engine varied with the type of oil that lubricated it. In addition, there is some discussion of the modifications that were made to the engine to enable the exceptional fuel economy performance of this vehicle. In addition to this study, results are presented showing how the viscosity-temperature-shear rate profile of a lubricant can be “designed” to give low friction in a particular engine.