ECS Tuning engineered 2-Piece semi-floating rotors offer real world benefits that can be felt on both the street and track! Our 2-Piece rotors combine the advantages of weight savings and rapid heat dissipation to provide a rotor superior to stock while preventing warping and extending component life. The 15% reduction of unsprung weight by (2 pounds per rotor) improves handling characteristics under all situations. This reduction in rotational inertia allows for quicker acceleration, decreased braking distances, and more responsive handling. Features include: Aluminum hats: To save weight, each rotor ring is bolted to a lightweight aluminum hat made from high quality 6061 aluminum, and hard anodized with an attractive matte black finish that is both durable and corrosion resistant. Gray cast iron rings: Long known for its wear resistance and stable friction characteristics, cast iron is favored for brake rotors due to its ability to absorb and dissipate large amounts of heat. 2-Piece construction: Conventional rotors are unable to cope with the stress of drastic heat fluctuations and are prone to warping. ECS 2-Piece semi-floating rotors allow the radial expansion of the rotor ring - preventing warping. Heat treated: Heat treating further reduces the tendency for rotor cracking by reducing internal rotor stresses. Directionally vaned: Conventional S4 rotors are straight-vaned, and rely on an inefficient centrifuge-like effect to evacuate hot air from within the rotor. ECS 2-Piece rotors feature curved, directional veins that accelerate air away from the rotor at a higher velocity, leading to consistent, rapid cooling. Drilled and slotted: 2-Piece rotors are cross drilled to promote cross ventilation for improved cooling as well as slotted to clean brake pads and carry away water and brake dust. Cleaner brake pads result in faster, more consistent stopping. Drilled holes are chamfered while slots are machined with a ball end mill - both to prevent cracking that may be present on improperly machined rotors. Overall weight savings: This particular ECS 2-Piece rotor weighs only 11.2 lbs compared to a stock S4 rotor 13.4 lbs. Lighter rotors reduce unsprung weight and rotational mass to improve both braking and suspension performance. Manufacturing quality: Non-friction ring surfaces, including internal vents, are painted to resist salt and other corrosives. Ground braking surfaces ensure rings run parallel, and pads bed easily. Includes ECS Stainless Rotor Set Screws to eliminate rusty factory fasteners
