Nowadays, the need for reductions on emissions caused by fossil fuels combustion is getting higher as well as the need for increasing the energetic efficiency of combustion engines. To attend this demand, a higher number of studies on this field are being developed to find ways to produce more eco-friendly engines. The present work is focused on validate the most precise method to be used for ignition delay calculation on internal combustion engines using diesel-biodieselethanol blends as well as relating the ID, efficiency, cylinder pressure and fuel injection point. For this study, a Matlab computer software routine was developed to adjust the data created during a test previously performed in order to calculate the ignition delay by different methods, energy efficiency, specific consumption, maximum pressure and its position. Based on this data, it was possible to prove the most effective method and that the efficiency does not necessarily reduces with the ID reduction.