MANETs are infrastructure less networks where each node must cooperate in the multi- hop routing process. Due to inherent characteristics such as dynamic topologies, band-width constraints, Energy constraints and distributed operation makes it a challenging area. Among the different categories of routing protocols, proactive routing protocols category is opted for the present study. In proactive routing protocols, Source Tree Adaptive Routing (STAR) with Least Overhead Routing approach (LORA) is chosen because it has less Network load when compared to Optimum Routing Approach (ORA). From the previous study of STAR routing protocol, it has a significant affect at lower mobility for all network sizes. In this paper, the most significant factor is identified to enhance the performance of defacto STAR routing protocol to support real time communication considering network size, mobility speed and Time to live (TTL) with response metrics Throughput, End-to-End Delay, Average Jitter using Taguchi Design of Experiments. At different network sizes with different lower mobility values, TTL is found as the most significant factor. We simulated the performance of STAR using QualNet simulator. According to the characteristics of a network routing protocol TTL plays a vital role. If TTL is too low, connection cannot be established and if it is too high energy consumption increases, which in turn affects the network life time. Our DOE experimental results revealed that, TTL is the most significant factor to enhance the performance of defacto STAR for MANETs to support real time communication. So, we conclude that our experimental results are strengthening the theoretical concept of the time-sensitive configurable parameters of the STAR routing protocol.