In the present work, a 4 cylinder, 5.3 liter, Direct Injection Diesel engine producing 140 kW rated power was upgraded to a higher power rating of 170 kW complying with Euro V emission norm. The exhaust after treatment strategy was changed from Exhaust Gas Recirculation (EGR) to Selective Catalytic Reduction (SCR).1-D thermodynamic simulation was used to simulate the performance. The simulation model was calibrated for performance parameters with the test results available from the 140 kW engine. This model was used to carry out the turbocharger matching for the 170 kW engine using the Simplified and Full Turbocharger model. A parametric study was carried out for the variables like Compression ratio, Start of Combustion shift and Compressor pressure ratio in view of the target Brake Specific Fuel Consumption (BSFC) and Peak firing pressure limits. The finalized model parameters were used for carrying out a Full throttle and Part throttle performance at selected operating points. An altitude simulation was carried out to see the turbocharger performance at an altitude of 1500 m.Simulation of Pollutant formation was carried out for the 140 kW base model by calibrating the model parameters to match the test data. The study was carried out using the Mixing Controlled Combustion (MCC) model. This calibrated model was used for predicting emission for the new engine power rating. The predicted emission trend was used to fine tune the model performance parameters before taking the new engine to the test bed which resulted in considerable savings of testing time.