Abstract. Alternative fuels such as biodiesel, bio-alcohol and other biomass sources have been extensively research to find its potential as an alternative sources to fossil fuels. This experiment compared the performance of diesel (D), biodiesel (BD) and diesel-organic germanium blend (BG5) at five different speeds ranging from 1200-2400 rpm. BG5 shows significant combustion performance compared to BD. No significant changes of power observed between BG5 and BD at a low speed (1200 rpm). On the contrary, at higher speeds (1800 rpm and 2400 rpm), BG5 blend fuel shows increased engine power of 12.2 % and 9.2 %, respectively. Similarly, torque shows similar findings as engine power, whereby the improvement could be seen at higher speeds (1800 rpm and 2400 rpm) when torque increased by 7.3 % and 2.3 %, respectively. In addition, the emission results indicated that for all speeds, CO 2 , and NO had reduced at an average of 2.1 % and 177 %, respectively. Meanwhile, CO emission had slightly increased compared to BD at low speeds by 0.04 %. However, the amount of CO released had decreased at an average of 0.03 % as the engine speed increased. Finally, measurement of O 2 shows an increment at 16.4 % at all speed range.