I posted this in the NX forums because I own an NX. But, this is applicable to your cars because we share an engine. Thought you would have interest.

https://www.clublexus.com/forums/nx-...l#post10443027

 

Lightening a vibration damper is never a good idea.

 

 

I am standoffish on the hole drilling idea. 1) I think it is the home/DIY way of lightning. I say this because the ability to drill holes but staying balanced would be an engineer's nightmare. 2) A lathe is taking off material in a uniform manner.
Yeah, reduction of diameter would reduce dampening inertia greatly. This is why I didn't do it on the first go round. I want to stay at this level but the delta inertia of only 0.0821-newton meters makes it seem pointless on paper. I even took videos of me revving it before and after and could not tell if there was a speed change. Hell, even that could be subjective because we don't actually control the throttle.

You're looking at a very complex engineering concept in a very simple manner. A lot of research is required to fully understand why a dampener and a weighted pulley is used. I can tell you, the crank assembly is balanced as a unit which greatly reduces the need of a dampener. As well, There is still a harmonics dampener in place. That is the rubber separator (that absorbs vibration) between the flywheel of the pulley and the actual pulley. I did not remove that. Yes, I removed the flywheel material but that is not going to hurt the engine. On daily driver economy vehicles, the engineers add weight to the rotating assembly to help in smooth rpm transitions. This increases inertia which kills power but they are not chasing power. That is what I am removing, the unnecessary weight. This is also why I did not take off a large portion.

But let me play Devil's advocate. Let's say I did remove the whole dampener. I just replaced the pulley with an ultralight solid metal pulley. For modern engines, this is still not a death sentence. The ideologies behind engine harmonics are decades old when engines had just sad machining tolerances. Modern engines are not going to get a level of harmonic vibration that causes the connecting rod to touch a bearing or some other possibility of material harmonics. Oil technology is light years from what it once was, the moving parts are balanced to precisions not heard of before, the engines are electronically monitored and controlled to NASA like levels... etc. I have owned an Evo 9 with a solid pulley, no problems for years. I own a Mini Cooper S with a solid pulley, no problems for years. And both of these engines were tuned as high as the stock internals would allow. That means the internals are harmonizing (vibrating) and exerting much higher forces on the oil and bearings than our stock engine ever will.

I can see and understand your reluctance though.