Designing and creating a Lightweight pulley

[dasicvtec]

Hi

Id like to design and create my own lightweight pulley. Id like to make the alternator and water pump pulley into aluminum. This really is more of a side project for me as the performance gain is negligible(probably none at all - but its extra bling!) but i want to learn how i can create my own parts.

The alternator pulley (pictured) only weighs 400g. Although if i do this project and complete it, then i don't see why i cant create a custom Under drive pulley (which connects to the crankshaft). I don't have Air con or power steering in my car so i can delete one notch/belt section on the pulley. The crankshaft pulley is made out of steel/cast iron and weighs 2.5kg so savings could be significant if.

Here is a pic of the original pulley.


At this point in time, the way i think something like this is created is by the use of a CAD program. So id learn and use a CAD program which should create a design of it, then i would take the design/saved file i create to a Machinist and they would use there own CNC machines to create it from aluminum ?

Any help would be appreciated. Thanks

note: please don't start about how a lightened under drive pulley is bad for the car because it unbalances everything. thanks