Originally posted by StewartFan20
What has the bigger impact on shock dampening? Piston hole size or oil weight?
I'd say both. The piston hole size has to do with "pack". That is the speed which oil can travel through the holes. When it reaches a certain speed it almost locks up. I think that comes into play more in off road and jumping, but it effects on road as well.
You need to keep in mind the weight of the shock spring and dampening of the shock must be close or when you find a combination you like try to maintain it. If you go to heavier springs, you probably need to increase you dampening as well. It all plays together.
Not sure on HPI pistons, but when I ran Associated one piston size to the next was approximately 5 wt. of oil change. So if you went from a #2 to #3 piston you drop down 5 wt. in oil to have the same dampening effect. HPI pistons seem a little closer together between hole size so I would guess maybe only 2-1/2 wt. of oil between, but I'm sure, maybe Eric can answer that.