<div class="section abstract"><div class="htmlview paragraph">NVH analysis based on numerical simulations before actual test vehicle is available becomes common process in the automotive industry. Furthermore, the latest work scope is extending even to conceptual study in the very early design stage, beyond traditional numerical simulations simply using 3-D CAD data. In case when reasonable information is provided at this very early vehicle development stage, a better decision on the design concept would be possible, and subsequent design process can be carried out in more efficient manner. The core of this trend is that it allows us to predict vehicle performance at the conceptual design stage without 3-D CAD data, and then, with this prediction, to suggest meaningful design directions for next stage. From this point of view, FRF-Based Substructuring (FBS) methodology has potential to be used as an appropriate tool for this purpose. Because running FBS technique takes relatively very short computation time for an individual model, large amount of computations for various combinations are made possible, which are virtually impossible to implement with the conventional finite element analysis. In this research, a conceptual analysis in the early design stage on a small-sized passenger vehicle has been conducted using FBS method. After converting the Finite Element (FE) full vehicle into the FBS models of each major system and establishing the FBS model database with about three hundreds of combinations, it is examined to select the optimal combinations for improving the road-noise. Based on these results, the design guide lines on each system for the improvement of road-noise performance as well as cost reduction have been proposed before detail 3-D design data is released. In addition, it has been shown that the approach based on FBS database is also very useful in the target setting regarding NVH related performance on each individual system.</div></div>