harmonic increase with ud pulley?

I was wondering, with the installation of any ud pully away goes the rubber dampner that is integrated into the stock crank pulley, anybody every run into a problem with vibration with a ud pulley? Ive seen entire bottom ends get wiped because the harmonic balancer shifted and didnt absorb any of the twisting action of the crank just wondering before I bolt the ud on the new engine lol

There was discussion about this on the teamzx2 forum.

[url=http://www.teamzx2.com/http://forum.zx2ms.com/phpBB3/viewtopic.php?p=142379#p142379]http://www.teamzx2.com/http://forum.zx2 ... 79#p142379[/url]
And before you ask, the one from the Focus does not work. Another great mod, and cheap to, is the UDP (under drive pulley). It is a lighter and smaller crank pulley that slows down the assesories of the engine (water pump, altenator, etc.) to prevent some of the parasitic drag caused by these devices. Since our stock crank is internally balanced there are no problems with changing the crank pulley. We don't have to worry about the 'harmonics' when swapping out the pulley. [b][u]Some engines have a balanced crank pulley and would have problems if swapping to an unbalanced UDP, lucky for us, this is not the case.[/b][/u] Powder has the smallest and lightest pulley, you can usually find a group buy going on in the 'group buy' section. Ford Racing and ZXTuner sell them as well. Whichever one you buy, make sure it comes with a belt since the new belt will have to be shorter.

Just to add to that I did the Ford Racing UDP kit, no problems.