It's called internally balancing. Stock Dmax engines are externally balanced, meaning there is weight added to the damper and flywheel.
We will press slugs of Tungsten alloy into these holes which is about 1.7 times as heavy as the parent crank material.
This will enable us to remove all of the extra counterweight from the flywheel and harmonic damper.
Having the weight located in the front counterweight of the crank where it belongs, instead of 6 inches in front of the #1 main bearing (as it is stock) where it has tremendous leverage on the crank, helps to extend the crank and bearing life significantly.