Almost all studies agree that adding 1% to 2% (% v/v) of biodiesel improves fuel lubricity.7,11,16-20 Several studies
have found that there is no longer improvement in lubricity when a certain concentration of biodiesel is added into the
blend with diesel fuel, this optimal concentration ranging from 2%16,21,22 up to 15%.23 The same was reported when
Fischer-Tropsch (FT) fuel was used as a base fuel. In this case, the corrected wear scar diminished from 672 μm (pure
FT) to 195 μmwhen 2%of biodiesels obtained fromdifferent feedstock was added.21 Contrary to most of the literature,
Bhatnagar et al.24 reported an almost linear decrease in wear scar as biodiesel concentration was increased in the blend
(tests were made with four Indian indigenous nonedible vegetable biodiesels in a concentration up to 100%).