The higher strength iron will have lowewr damping capacity and lower heat capacity. This could cause increased noise and reduced life from heat checking especislly if used in hard braking condition.
Density of Iron (#/in3)= 517-13.95*%C -5.67*%Si-4.43*%P
This formula is per H.T. Angus published in his book "Cast Irons Physical and Engineering Properties"
