I've been thinking about this for my car, which is turbocharged with AC, but PS removed. The stock crank pulley has a 5.5" diameter for the AC, but the PS step next to it has a 3.5" diameter. The reason I want to move the belt to that pulley is mainly for space, as it gives and extra inch for wastegate placement, and even more if I move it upwards too. I don't boost w/o turning the A/C off, so I don't care about high rpm parasitic loss.

The obvious problem is the compressor's reduced speed, which is ~36% less. Since 90% of my driving when the A/C is on is on the highway, should I worry about the compressor speed reduction? I'm guessing the worst case scenerio is that it won't pump enough R-134 when the engine is idling. I could increase idle to compensate, and I know my car increases idle even more when AC is on.

BTW the AC system will get a fresh recharge next year, right after being professionally 'vacuumed'.

 

Nobody has a clue? Thats uncommon...