In a perfect world, you'd get nothing but water and carbon dioxide out the tailpipe:
2C8H18 + 25O2 > 16CO2 + 18H2O (octane reaction only... there are other hydrocarbons in gasoline that would follow the same pattern, dunno how the detergents and other additives react)

Someday I might even beat that wascally kenny!

No whammies... no whammies... no whammies...