The purpose of this paper is to present how new tools enable engineers to go further in the improvements in lead-time, mainly through an “up-stream” integration of numerical data base. It is now possible to consider a fully integrated CAE (modelization), a rapid prototyping process and a fast cost-estimation at early steps of product engineering. The development of Heating, Ventilation and Air-conditioning unit (HVAC) is a good example.The automotive Industry requires more and more efficiency in product engineering to achieve objectives of Quality, Cost and Lead-time. The use of modern methodologies based on Simultaneous Engineering has highly contributed to improve performances of integrated project teams for quality goals (QFD, FMEA, experimental plans, etc…), and for reduction of costs (Value engineering, Value analysis, DFMA, etc…). Improvements in lead-time have been made possible, by development of standardization and approved sources, as well as by generalized use of CAD-CAM for direct transfer of numerical data from the design of parts to the design and machining of tooling or mold.However, engineers have now new tools for different steps of developments, mainly for early design (modelization of air-flow and heat transfer, for HVAC design), rapid prototyping for performance assessment, and rapid costing for major choices.