The latest state-of-the-art innovation in realistic fluid catalytic cracking (FCC) catalyst testing is the short contact time resid test (SCTRT). This unit has been especially developed for residual hydrocarbon feed and solves limitations of other lab-scale testing units by allowing instantaneous mixing (injection time of I second) of catalyst and feed. Its unique features make the SCTRT an excellent tool for catalyst development and for screening and evaluating FCC short contact time operations in the laboratory.