I think the alternator idea is a bust
Back to thinking the Balcam compressor is the way to go. I think if I adjust the drainpipe output by running 4" or 6" pvc the full length of the pipe plus 6 feet or so. Make it an overshot wheel, which I've seen is more efficient. I have to do more tests, but if I can get 3/4 gps, I think I will be spinning about 60-70 rpm, which should spin the compressor about 100 rpm with a 2:1 pulley setup.
