Quote:
Originally Posted by Spuds
I've offered to do the math on pulleys twice now and will repeat it here. Math does not lie or exaggerate. It has no motivation. It simply is. I just need stock numbers for the model.
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Math do not lie, but you have to model the problem correctly. You asked twice about total weights and diameters. A total weight and diameter is enough ONLY for the solid pulley. On the OEM pulley you have two different pulleys the one inside the other joined together with a rubber. You need the diameters of both and the weights of both. No one can really provide these numbers, unless someone takes apart the pulleys and measures the two weights. Then you have to create a model that the inside pulley is rotated by the center hub and the outside pulley is rotated by the inside pulley. With such model you would find that the rotation inertia is MUCH BIGGER and it not only relevant to the weight difference. As said before it is a complex problem and there are unkonwns in the equation (i.e. the weights of the OEM pulleys). It is much easier to make some measurements and see how the car behaves with standard tools like the virtual dyno app.