The Hybrid Electric Vehicle Team (HEVT) of Virginia Tech is currently going through several modeling and testing stages to develop models that represent the P3 PHEV powertrain the team is building as part the EcoCAR 3 competition. The model development process consists of several major steps. First, Model-in-the-Loop (MIL) testing is conducted to validate a conventional vehicle model, down-select a desired powertrain configuration, and generate initial vehicle technical specifications. HEVT is pursuing a performance powertrain that balances high performance with minimal energy consumption. Initial MIL modeling results yield an IVM-60 mph time of 4.9 seconds and an overall UF-weighted 4-cycle energy consumption of 560 Wh/km. MIL modeling provides an initial reference to compare subsequent vehicle modeling. Following the MIL process, Software-in-the-Loop (SIL) is used to develop a vehicle model from the ground-up that facilitates the transition to Hardware-in-the-Loop (HIL) testing. This SIL modeling enables the implementation of features such as active fuel management (AFM), regenerative braking, and the creation of an organized input/output structure between the plant model and the hybrid vehicle supervisory controller (HVSC) code. In the SIL model, the implementation of AFM and regenerative braking leads to a 16% decrease in total energy consumption. Furthermore, consideration of traction limitations provides significant variation in acceleration results. By pursuing a multi-step modeling process, HEVT is able to begin the process of designing and implementing a HVSC code and vehicle model that meets team goals and VTS.