Abstract: - In the present years, population of vehicles increased enormously which increases the demand of fossil fuel, The availability of conservative fuels decreased continuously, these reasons makes to find the alternative fuels especially biofuels . The use of biodiesel considerably reduced emission and increase the performance of the engine. Now a days researchers have reported the possibility for the production of biodiesel from non edible oil jatropha curcus , pongamia pinnata etc. There is a best source of raw material that is calophyllum inophyllum oil for biodiesel production. In present study calophyllum inophyllum is used as fuel in C.I engine.Blends such as CIME10, CIME20, CIME30, CIME100 are taken for the experiment From this blends CIME20 gives good results and for this blend Isobutanol is added as fuel additive with concentration of 10%,15%. The Performance was improved and emissions were reduced by using Isobutanol with CIME20.