Simulating rotating turbomachinery, such as aircraft engines, demands high-fidelity, scalable CFD frameworks capable of resolving complex, moving-domain flows with industrial accuracy. A critical bottleneck in such simulations lies in the efficient and robust coupling of rotor-stator interfaces via zonal mesh interfaces, where clipping of matching faces and data exchange impose significant overheads. In this work, we present a systematic performance analysis of the zonal interface implementation within the TRACE CFD solver, leveraging code profiling and large-scale runtime measurements to identify architectural inefficiencies. We introduce a suite of targeted optimizations spanning algorithmic refinement, data structure reorganization, parallelization enhancements and load balance improvements. We achieve up to a 5× speedup in the computational parts of the interface and up to a 2x speedup for the necessary communication, enabling efficient simulation of industrial-scale turbine geometries. This contribution exemplifies how systematic optimization and architectural awareness can transform legacy CFD components into scalable, high-performance building blocks for the next era of predictive simulation.