ASP Underdrive pulley systems increase engine horsepower by reducing the amount of power required to drive external engine accessories (i.e. alternator, power steering, water pump and air compressor) which rob horsepower from the engine. By replacing factory-sized crank and accessory drive pulleys with a resized ASP pulley, the accessories are slowed, resulting in more horsepower available to the drive wheels. Typically, a set of Auto Specialties street pulleys will increase 12-15 horse power, and increase mileage by 2 to 3 MPG. All ASP pulleys are manufactured from Billet Steel or Aluminum, exceeding factory quality. *actual part may vary from picture shown above
