Quote:
Originally Posted by UBERCOACH
Trevor,
Thank you for the very nice explanation of the additional dampening function of the crank pulley. Now I understand why mine is making a noise. I'm considering buying one of Dayle's lightweight pulleys. I noticed in the comparison photo of Motorsport Warehouse's aluminum pulley and the OEM pulley, you can see what I think is dampening material. Any reason not to go with the much lighter pulley?
Thanks for your expertise,
Ubercoach
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You are putting a curly one on me.
The lightweight pulley will be one piece and will incorporate no form of dampening. This will mean that you have done away with something the designers considered necessary, in spite of there being added production costs.
It will be explained that many here have been running solid pulleys for a very long time and there have been no reports of a crank failure. The flexible belt drive from the pulley also comprises an excellent torsional vibration damper, not present in a chain or gear driven set up. Have the designers been over conservative? That is the question which you must answer.
I am willing to stick my stick my neck out and say that there will be no gain in acceleration of any consequence, as a result of changing to lighter pulley. Consider the reciprocating weight and diameter of the pulley as a proportion of the total reciprocating weight of the engine as well as other driven mass, and you will appreciate the reason for my certainty. What is more, a lighter pulley can in no way increase power output.
A smaller pulley will reduce the parasitic load imposed by several auxiliaries, but their efficiency will be reduced. Any power saved/gained will be marginal and for normal purposes not worthwhile.
