4.6L Underdrive Pulleys

The Steeda Underdrive Pulleys are a performance upgrade specifically engineered for 2005-2010 Ford Mustang GT models equipped with the 4.6L engine. As a leader in underdrive pulley design for these engines, Steeda was the first to achieve SFI approval. These pulleys are not just a simple replacement; they are designed through a unique partnership with Ford's technology transfer program to ensure proper torsional vibration dampening characteristics, a claim no other manufacturer can make. The primary function of these underdrive pulleys is to slow down accessory speeds by approximately 25%. This directly reduces the parasitic drag on the engine, freeing up valuable horsepower and torque that would otherwise be consumed by belt-driven accessories. Owners can expect an increase of up to 10 horsepower, along with noticeable improvements in gas mileage. The design features a one-piece nodular iron construction with an injection-molded rubber element, using special rubber compounds selected for their ability to absorb torsional vibrations and withstand the demanding underhood temperatures. Steeda's testing indicates their pulleys are more precisely tuned than those of competitors. These pulleys are manufactured under stringent quality certifications, including ISO/TS16949, QS-9000, and ISO 9001. The product is noted as not being CARB exempt and is therefore not legal for sale or use in California. Installation is described as a full replacement bolt-on damper, with an approximate time requirement of 2 hours. The kit includes both pulleys and necessary hardware for installation.