In the last few decades biodiesel has proved to be the best alternative for the conventional diesel in many applications. Due to ever increasing demand of the mankind, the fossil fuels are depleted so much that in the near future oil scarcity is inevitable. The environmental impact that is caused by conventional diesel can be greatly reduced by using biodiesel. The present study experimentally investigates the usage of preheated crude pongamia oil (CPOP), pongamia methyl ester (PME) and diethyl ether (DEE) biodiesel blends on an unmodified diesel engine running on its full throttle. Preheating crude pongamia oil reduces its viscosity to a great extent, which is always an issue with biodiesel fuels. In the present study the performance and emission parameters are evaluated for DBD 1 (CPOP 60% and D 40%), DBD 2 (PME 60% and D 40%) and DBD 3 (CPO 60%, DEE 15% and D 25%). The experimental data obtained for performance and emission parameters for biodiesel fuels are checked in par with mineral diesel. For all the biodiesel blends, the trend for BTE is found increasing whereas BSFC followed a decreasing trend at all operated loads. Particulate emissions except HC and NOx are lesser in biodiesel blends than diesel due to the presence of dissolved oxygen. Also the addition of diethyl ether to crude pongamia has significant impact on performance improvement and reduced emissions when compared to other blends. From this experimental study it is concluded that pongamia oil because of its rich availability in India can be the best fuel for blending with diesel and using for small and medium scale energy producing vehicles.