Biodiesel is becoming a common propulsion fuel, as various countries around the world add it to mineral diesel oil, usually as B2 or B5. In low percentages there is no major difference to diesel fuel in terms of power delivered and emissions, but as the percentage rises some alterations are evident on the engine output. These alterations depend on the type of engine, being different from engine to engine.Two Ford Ranger PickUps were used in this study. The diesel engines were different, one a high compression ratio with an old pump-distributer fuel injection system and the other using a common rail system were tested with 5%, 50% and 100% biodiesel-diesel blends on a rolling road dynamometer. The control system of the engines was stock, with no alterations for the various blends.The results show the expected trend in terms of power and emissions, but the differences between the engines display interesting results that can be traced to the differences in engine specifications.Two similar newer engines were tested in a long road trip in similar vehicles, one with diesel and the other with biodiesel. The results confirm the laboratory tests in terms of acceleration and fume production. Fuel consumption, in volume of fuel and energy, was also determined.