Explain: NST Underdrive & MI pulley

[evo165]

Hi all,

Currently I am on NST 10% under-drive pulley. I knew that NST have a problem with customer service etc. So far no mechanical problem on me yet.

I just need to know the exact different on the output of the 2 given pulley.

1. NST 10% smaller than OEM pulley size and light.

Since this is 10% smaller in size, It will reduce the engine load by 10%?

2. MI OEM size pulley. I read that this is a tad lighter than the NST 10% UD pulley.

Since this is OEM size, the loading to the engine is the same BUT just a MUCH lighter pulley? Am i correct?

Overall, what does each pulley can make the driver butt feel? Kindly enlighten...