The fuel consumption flow rates are measuring accordingly from two flow meters and also from the chassis dynamometer in advance mode. Brake specific thermal efficiency could be calculated from fuel consumption, times, power input and power output of different fuels from further mechanical analysis of the real engine performance parameter. For the performance test, the experiment begins with mainly double checking on safety practices of both diesel operation and HCNG DDF operation ensuring no leakages of any sort of hazard and dangerous fuels were leaking during the test and afterward.