Silicon brass of LTs16K4 grade has found wide application in art castings due to its high process properties, beautiful gold-yellow color, and the possibility of deposing various decorative coatings. In this study, the possibility of increasing its fluidity by varying the chemical composition in terms of GOST (State Standard) 17711-93 is investigated. To measure fluidity, the method of vacuum suction is used. This method reveals the change in this characteristic upon adding from 0.1 wt % alloying element (Zn, Si, Al) and shows a high convergence of results. The experimental data are subjected to regression analysis. The quantitative evaluation of the degree of influence of zinc and silicon on the fluidity of silicon brass is found and an adequate mathematical model and the response surface of the fluidity function are constructed. The optimal overheating temperature providing the maximal alloy fluidity upon minimal zinc loss is determined. The results of this study can be used when fabricating art and industrial castings of silicon brass LTs16K4, as well as in other branches of metallurgy and foundry production.