First - Where were all you guys, when I was building my AC System
Definitely some "lively" discussion going on in this thread....
As for the belt vibration, this caught my attention, as I literally just posted on this same topic. I designed my own system with a rotary vane compressor, so I figured I was the only one with this problem, but it looks like others have seen this with the original York recips and the conventional Sanden and Denso swash plate compressors.
What I found is that V- belts will resonate at certain RPM ranges. Sometimes it is severe, and you can feel it in the car, and other times you never notice, unless you are looking for it. Usually, this vibration can be mitigated by increasing or decreasing the belt tension, or by changing the mass of the belt (use a thicker or thinner one to raise or lower the frequency at which it vibrates). When that doesn't work, you have to use idler pulleys to effectively add stiffness to the system at strategic points. One will usually do the trick, but for my system, I found out that my belt actually had dual vibration modes (I had to use a strobe light to actually see this). The ultimate fix was to use 2 idle pulley's on the top side (slack side) of the belt. The bottom of the belt is under the highest tension, so perhaps that side does not go into resonance until above 8000 RPM or so. Needless to say, mine looks great up to 6000, and I'm not testing it any further. I posted pictures of my fix on DIY Air Conditioning for old Porsches.
Keep up the good work, guys. Even the (sometimes hard to understand)jabs back and forth have good information to gleen for the rest of us