The fundamental aim of extended expansion concept is to achieve higher work done, which in turn leads to higher thermal efficiency. This concept is compatible with turbocharged engines incorporated with ceramic laced components. Higher efficiency in four stroke engine was achieved by delaying inlet valve closing and exhaust valve opening with the aid of cam lobes. Extended Expansion in diesel engine (miller cycle) was made possible by reducing compression stroke which in turn results in a longer expansion stroke. Experimental investigation was carried out under different load condition conditions on a four cylinder turbocharged DI diesel engine under low heat rejection conditions by using partially stabilized zirconia (PSZ) coating of thickness 0.5 mm to the combustion chamber with modified valve timing. The results was observed with 6% of reduced specific fuel consumption and 13.5% increase in peak pressure, when compared to conventional diesel engine. Emissions of hydrocarbon is reduced where as NOx is increased.