The authors introduced a new configuration based on the cross-sectional variation of the turbine volute acceleration section by means of a specially shaped element located in the inlet part of the volute. Said element could move either in the direction of incoming gas flow or in the opposite direction to change the inlet cross-sectional area. As a result, this configuration lead to reductions in CO of 10.1%, PM of 19.23%, and specific fuel consumption (SFC) of 0.6%. Another experimental VGT study, by Wahlstrom and Eriksson [11], looks at a two-stage configuration. The performance of which is later analytically investigated by Galindo et al. [12]. A review on various turbocharger concepts configuration by Aghaali and Ångström [13] discusses the best fit for a given set of operating conditions. Although some optimization studies have been performed for compressor [14] and pump-turbine [15] vanes, no optimization study on the VGT inlet guide vane geometry could be found. Accordingly, in this experimental study the main objective is to improve the efficiency of VGT turbines by means of vane configuration optimization using central composite design (CCD). Hereby, the CCD method will be compared to a theoretical model based on free space parameter (FSP) theory [5].