Your car's power steering pump and alternator are powered by a belt connected back to the crankshaft pulley. Spinning these two accessories draws precious horsepower from your engine. NEUSPEED's powertrain engineer, using sophisticated CAD software, performed a mass properties analysis to determine the ideal weight and diameter of the crank, power steering and alternator pulley. By manufacturing the NEUSPEED pulleys out of 6061-T6 aluminum to reduce weight, and resizing the diameters to slow the drive speed of the alternator and power steering pump, a 5hp gain at the wheels is achieved. Made from 6061 T-6, hard anodized in black. Does not fit the 24-valve VR6 engine