A local and global environmental concern regarding automotive emissions has led to optimize the design and development of Power train systems for IC engines. Blow-by and Engine oil consumption is an important source of hydrocarbon and particulate emissions in modern IC engines. Great efforts have been made by automotive manufacturers to minimize the impact of oil consumption and blow-by on incylinder engine emissions. This paper describes a case study of how simulation played a supportive role in improving piston ringpak assembly. The engine taken up for study is a six cylinder, turbocharged, water cooled diesel engine with a peak firing pressure of 140 bar and developing a power output of 227 KW at 1500 rpm. This paper reveals the influence of stepped land, top groove angle, ring face profile, twist features with regard to tweaking of Blow-by & LOC. Relevant design inputs of engine parameters were provided by the customer to firm up the boundary conditions. Predictive simulation techniques with extensive DOE were carried out to develop an optimized ringpak with better ring stability. Simulations were performed under the lubrication condition, mapped with the experimental results, to investigate the influence of piston ring assembly on blow-by, oil consumption and friction. Simulation results have been relatively compared with each parameter along with supportive DOE. Proto samples made with optimal assembly combination were tested and results are on par with simulated values. Improvement in oil consumption by 30 % and blow-by reduction of 30 % was achieved. The results predicted through simulation were comparable with experimental data.