Current generation of metal monolith using binary catalysts Pt/Rh (5:1) is simulated for transient temperature and conversion inside a catalytic converter during warm-up. A new concept in mass transfer on a catalytic combustion is introduced in this model for improving accuracy is known as Reynolds analogy. Design parameters and operating conditions are investigated for its influence on solid temperature and conversion of species. New patterns of precious metal loading have been investigated for metal savings and maximum conversion efficiency. Satisfactory validation of computed data was observed.