AUDIOZ A4

Anyone care to comment on the following? Im still researching the effects of a UDP - but the deeper I dig the more it seems like a misconception that its a bad idea.

Anyway - comments welcome as this seems a very interesting topic for conversation

Quote" Based on your comments and his response I also did some more research (thanks for pointing out the other sources), and found for instance that Unorthodox claims that the concern about the lightened underdrive pulleys having an impact on the crankshaft harmonic vibration balancing is a misconception. Apparently, the late model factory pulleys have two problems they must overcome as a direct result of their own heft: to reduce audible noises and to provide torsional damping because of their heavy weight. Both of these problems are alleviated by the much lighter and perfectly balanced CNC machined replacement aluminum pulleys.

The other misconception is that the pulleys themselves are harmonic dampers, which again is not true. Apparently, the harmonic damper (if one exists since modern engines don't require one) is a separate piece on the crankshaft snout, attached to the crankshaft accessory pulley. Neither the harmonic damper nor the balance shaft have anything to do with replacing the pulley itself.

They also say that the factory pulley gearing is over-engineered for charging and spinning the other pulleys. In other words, even the reduced diameter pulley provides sufficient charge at idle for the alternator and accessories. However, conceivably you could even keep the same gearing ratio by replacing the other pulleys with smaller ones also." End Quote<ul><li><a href="https://forums.audiworld.com/a4/msgs/520689.phtml">https://forums.audiworld.com/a4/msgs/520689.phtml</a</li></ul>