<p>This paper presents a comprehensive study on multi-objective topology optimization of Aluminum Die Casting (ADC) alloy connecting rod using the Bacterial Foraging Optimization (BFO) algorithm. A baseline model of a car engine connecting rod is developed and implemented a gradient-free, multi-objective BFO framework for material distribution, focusing on mass minimization, compliance reduction, and natural frequency, factor of safety maximization. Manufacturing constraints specific to high-pressure die casting, minimum wall thickness and draft angles are integrated via penalty functions and directional density gradients. The methodology is validated through numerical experiments and compared with the well-known SIMP (Solid Isotropic Material with Penalization) algorithm. Featuring a solid rod baseline, detailed parameter settings, and original simulation results. Key outputs include the Pareto front of mass stiffness, frequency trade-offs, optimized designs with detailed dimensions, and comparative performance metrics demonstrating mass reduction up to 30%, frequency increase up to 18%, and compliance and factor of safety improvement up to 25% and 18.5% respectively. Factor of A sensitivity analysis of BFO parameters and a discussion on die casting feasibility conclude the paper. This work advances the field of topology optimization for die-cast assemblies by integrating a bio-inspired algorithm and practical manufacturing constraints, offering guidelines for lightweight and high-performance connecting rod designs.</p> Graphical abstract <p></p>