I enjoyed your article about harmonic damping and problem of using underdrivre pulleys. Since the thread is locked, I thought that I woulld approach it from a new thread.
I have a couple of questions: would using a lightened flywheel also add to this problem? If so, would any internal lightening of pistons, rods and even cranks also tend to create similar problems? Is the problem increased or decreased if the car is just used for short speed tests as opposed to long drives at top highway speeds? Also, what about the removal of balance shafts? Thanks for advice.

 

Lightened flywheel would probably add to the problem. The whole issue of torsional vibrations in the crank (& it's natural frequency) is too complicated for a simple answer. The only simple answer is a warning that you can break stuff. Weight, moment-of-inertia, and damping factors all contribute to an oscillating system, and you or I don't know all the information to analyze it properly.

Balance shafts are another story. They have more to do with gross vibrations and comfort.

 

I think he's talking about this thread (linked below).

https://www.hondaaccordforum.com/for...pulleys-35041/

 

Yes, that's it. (that article is a "sticky" and is locked.)