Porsche Repair: 79 911 air conditioning, crank shaft, piston compressor

Question
My 79 911 SC has an aftermarket AC unit that doesn't cool very well, vibrates, the belt runs hot as if it is slipping, and the unit puts enough load on the engine at idle that unless I set the idle high it sometimes dies at a stop. I have had a professional adjust and recharge the unit. Would or could a replacement unit give much improved performsance?

Answer
John there are a few things you can do to improve the integrity (leaks, vibration, loss of power) and upgrade the system.

Starting with the compressor we usually run what we all a "507" or in generic terms a wobble plate piston compressor, as opposed to a typical York crank shaft compressor (if that is what you have).

Leaks are resolve with changing to "barrier" hose lines.

Adding additional condensers will lower the refrigerant temperature and take the load off the compressor.

Additional vents improve the air flow in the cockpit.

And there are many more things you can do.

It all depends upon your budget and long term plans with the 911.

Here is an interesting site to read on improving your ac system:

http://www.griffiths.com/porsche/ac/ice/index.html