Open DB/Plugins/Trinity/Combat/Abilities/WizardCombat.cs. search for EnergyTwister and edit the stack count from 1 to 8.
// Energy Twister SPAMS whenever 35 or more ap to generate Arcane Power
if (!Player.IsIncapacitated && CanCast(SNOPower.Wizard_EnergyTwister) && !ShouldWaitForConventionElement(Skills.Wizard.EnergyTwister) &&
Player.PrimaryResource >= 25 && !Settings.Combat.Wizard.NoEnergyTwister &&
// If using storm chaser, then force a signature spell every 1 stack of the buff, if we have a signature spell
(!hasSignatureSpell || GetBuffStacks(SNOPower.Wizard_EnergyTwister) < 8))