New technologies in the fuel injection system have improved the performance of the CI engine. Even though the biodiesel is universally accepted as a suitable alternate fuel for the CI (compression ignition) engine, there have been limited study reported on its utilization for single cylinder CRDI (common rail direct injection) engine. Use of biodiesel with diesel in a CRDI engine reduces proportionate consumption of diesel. In the present study, performance and combustion tests were carried out with the CRDI engine using the B20 blend of mahua methyl ester in diesel on volume basis called (B20 MOME). This study was conducted on a CRDI converted variable compression ratio engine with toroidal shaped cavity in the piston adopted. The tests were carried out at three injection pressures of 400 bar, 600 bar and 800 bar and for three injection timings of 15° BTDC, 20°BTDC and 25°BTDC, respectively. The results of the combustion and performance tests with the CRDI engine were compared with the performance of a CI engine at specified operating conditions with mechanical injection system using diesel as the fuel. The results indicated significant increase in the performance of the engine with increase of injection pressure. At 800 bar injection pressure, brake thermal efficiency of 29.98%, 27.61%, and 26.98% was attained at 15BTDC, 20BTDC and 25BTDC, injection timing respectively using B20 MOME.