To RJC: How about an aluminum AC Pulley?

[V6UnderPressure]

I am not too familiar with the pulley of the AC, but I believe its a clutch. I am not sure if anything can be machined for it (pulley) yet still retain the function of it. But a lightened version for us guys who have AC still would be great to match with your other lightweight aluminum pulleys.

Scott

 

[Race Jace]

I made a few covers that screwed into the center threaded hole location but i never could make anything that did not look cheesy.

 

[notacarlo]

Is Cheesy a technical term?

 

[CTX-SLPR]

You'd need a steel ring for the electromagnetic clutch to work. I've not pulled my R4 out of the box so I don't know how its setup but on the A6 on my Nailhead the pulley floats on the shaft and the EMag clutch will grab it for engagement.
Making an AC pulley isn't as easy as just wittling up a pulley the clutch functionality is pretty unique to the setup though I think BMW has started using an EMag fan clutch.