Methods for cracking a hydrocarbon oil include contacting the hydrocarbon oil with a catalyst system in a fluidized catalytic cracking unit to produce light olefins and gasoline fuel. The catalyst system includes a FCC base catalyst and a catalyst additive. The FCC base catalyst includes a Y-zeolite. The catalyst additive includes a framework-substituted *BEA-type zeolite. The framework-substituted *BEA-type zeolite has a modified *BEA framework. The modified *BEA framework is a *BEA aluminosilicate framework modified by substituting a portion of framework aluminum atoms of the *BEA aluminosilicate framework with beta-zeolite Al-substitution atoms selected from titanium atoms, zirconium atoms, hafnium atoms, and combinations thereof. The FCC base catalyst may include a framework-substituted ultra-stable Y (USY)-zeolite as the Y-zeolite. The framework-substituted USY-zeolite has USY aluminosilicate framework modified by substituting a portion of framework aluminum atoms with titanium atoms, zirconium atoms, hafnium atoms, or combinations thereof.