GFB Evo 4-9 Under-Drive Crank Pulley w/ BeltIt might be hard to imagine how reducing the mass of a pulley makes a car go faster, but accelerating a heavy factory pulley from say 3000 7000 RPM in a second or two saps a measurable amount of torque. GFB Lightweight Pulleys reduce inertia by up to 85 percent, so most of the torque that used to accelerate the pulley can now be applied to the wheels. This Part Fits: Year Make Model Submodel 2003 2006 Mitsubishi Lancer Evolution 2015 Mitsubishi Lancer