The big difference between the two materials is the weight. The all-aluminum engine can weigh less than half the weight of a cast iron engine. Originally, the total weight of cars was not high, and the proportion of engines could not be ignored. The direct effect of weight reduction was the enhanced fuel economy performance. The weight of the engine also directly affects the driving performance of the vehicle. Since most cars are front-wheel drive, such as the weight of the front cabin is too heavy, the vehicle will cause excessive turning when turning; and the heavier the car, the longer the braking distance will be. .