I have heard mixed thoughts about them to my understanding they are good for all out race cars but for the street and longivity I would stick with the stock one because it is a harmonic balancer which is said to keep things balanced comparaed to a cast or billet pulley thus in turn prolonging engine life
Personally, I like lightened pulleys. The problem with me is that I've got a supercharger and finding lightened pulleys of stock size or bigger is a pain. They often have to be custom fabricated. On my next rebuild I'm planning to take the stock pulley and have a shop shave off everything except the serpentine belt.
i just want you to know that you have started a war....................
this is a VERY controversial topic. Everyone has different viewpoints on underdeive/lightweight pulleys.
just do some searching. i think someone on this forum has actually done some research and tests on them and concluded that they tear up your main bearings....................possibly transzex tested it.
i personnaly used to think it was a myth until doing further reading, but i still have doubts as to wether or not they are rough on the bearings. I dont think that i would run them unless my motor was newly balanced and if i did run them i would only run unorthodox. i dont want to risk something that big for something so little. gains noticed arent that large and the money can be better spent elsewhere.
u could hear the stranged sound from the pully....cos it is too loud after the lighten crank pully installed (may be mine is cheap alumin brand, bought from ebay)........i dont feel it's good obviously. D2 crank pully is so popular brand, but the pice is not cheap.