We spoke about increasing perceived horsepower through increased acceleration via lightening driveline components in the “lighten driveline section”. However there is another often ignored method of increasing acceleration in your vehicle. Lightening the rotating brake system components is such a method. By switching to lightweight rotors one can reduce the rotating mass of the wheels and increase gas mileage and acceleration as a result. It will take less horsepower to move the vehicle the same amount of distance due to the lightened weight. Reducing brake system weight can thus increase gas mileage by requiring less gas to move the car the same distance.
There are a few options to reduce your vehicle’s braking system weight. The easiest way is to use aftermarket lightweight rotors. One way to do this is use cross drilled rotors. Cross drilled rotors can have around 10% of their mass removed via the cross drilled holes in the rotor surface. Another common way to reduce vehicle rotating weight is by switching to a two piece aluminum rotor hat. A rotor hat is the portion that has the through holes that the axle threads slide through to bolt the actual rim onto the axle assembly. Aluminum rotor hats are simply that. Hats made of aluminum instead of a heavier cast iron or steel. They are specially bolted to the rest of the main rotor which cannot be made of light aluminum as it is used in the actual braking application. They can be significantly lighter than stock and reduce unsprung rotating weight by several pounds or more per tire resulting in significant increases in vehicle acceleration.
Not too many companies offer aluminum rotor hats so this may be a difficult item to source. Also, lightened aluminum hat rotors are generally very expensive and can be up to 6 times more expensive than regular rotors. So one must weigh the costs against the power gains. However the resulting gains in acceleration are similar to common lightening driveline mods.