A nodular iron alloy and automotive components, such as a crankshaft, are provided. The nodular iron alloy may include iron, about 2.2-3.2 wt % carbon, about 1.7-2.3 wt % silicon, about 0.2-0.6 wt % manganese, a maximum of 0.03 wt % phosphorus, a maximum of 0.02 wt % sulfur, about 0.2-0.6 wt % copper, about 0.1-0.4 wt % chromium, about 0.4-0.8 wt % nickel, about 0.15-0.45 wt % molybdenum, about 0.2-1.0 wt % cobalt, about 0.02-0.06 wt % magnesium, and a maximum of 0.002 wt % rare earth element(s). The nodular iron alloy may have a Young's modulus in the range of 175-195 GPa and an as-cast ultimate tensile strength in the range of 750-950 MPa. This alloy possesses favorable strength, stiffness and noise/vibration/harshness qualities, making it suitable in crankshaft applications. A method of forming the nodular iron alloy includes feeding a magnesium-based material into a molten iron alloy through a continuous system at a constant amount.