Originally Posted by
Maximo
I will disagree here.......I will not divulge all the results of my testing...But I will say with 100% certainty that the slug definitely adds top end power and reduces the vibrations in the engine.......I did multiple dyno tests on several engines..tested without slug, then retested the same day with the slug....Not only did the power after peak improve, there was also a noticeable reduction in the engines harmonics at higher RPM's...Not only did the engine carry power better after peak, it also pulled the dyno several thousand RPM higher before maxxing out....Adding a heavier flywheel has no such effect and showed absolutely zero difference on the dyno....... I wont pretend to know all the reasons why, but I can definitely verify the results with 100% certainty on the dyno....
The extra weight will not add power but I do not doubt when you say the dyno shows the engine producing more power and revving higher.
The extra weight may be allowing the engine to reach higher rpm and/or altering the point/s in the rev range where resonance occurs but there is always a trade off.
You can not "fix" engine balance, all you can do is alter the out of balance points to a range that suits the characteristics of the engine.