The rate of evaporation of gasoline varies with brand, grade and whether it's refined for summer/winter/high altitude/or racing etc. Also different compounds in the mixture evaporate at different rates.
Will also depend critically on the partial pressure of each of your volatile constituents in the gas space above the bath. This is a function not only of the atmospheric pressure (which you specify) but also of the degree of ventilation (which you don't).
Generally its assessed via the copper strip corrosion test (ASTM D130). A polished copper strip is immersed in the fuel for a period of time and then visually rated compared to a standard scale. Technically I don't know that temperature 'increases' corrosivity so much as speeds the reaction that's already there.
