No, normal petrol cars are not designed to run on flex fuel, which is a blend of gasoline and ethanol. Flex fuel vehicles (FFVs) are specifically designed to run on gasoline, ethanol, or any combination of both fuels.
FFVs have special fuel systems and engine components that can handle the corrosive effects of ethanol, which is more corrosive than gasoline. In addition, FFVs have sensors that detect the ethanol content in the fuel and adjust the engine accordingly.
If you were to put flex fuel in a regular petrol car, it could cause damage to the fuel system and engine, leading to costly repairs. It's important to always use the fuel recommended by the manufacturer to ensure the optimal performance and longevity of your vehicle.