What kind of compressors are you guys with a/c running on your cars? Stock or Sanborn type? I'm not concerned with the a/c being all stock under the hood! All so are you running R 12 or 134a? I want good cold functioning a/c
I’m not an AC expert by any stretch, there are GS65 members that I’m sure know much more than I do. However, I have restored a couple AC systems and learned some lessons doing so. My thoughts.
I’ve replaced GM A6 compressors with Sanden compressors in two cars, serviced them with 134, adjusted the POA valves and they cool just fine.
Selection of refrigerant plays only a small part in the overall efficiency of our AC systems. The condition and internal/external cleanliness of the condenser and evaporator as well as a properly functioning expansion and POA valves play a much greater role. It is also important that the ducting, blend doors and water shut off are all functioning well. Servicing is critical, not enough or to much refrigerant will greatly degrade performance. When converting to R134 you normal service to 80% of the R12 service volume.
I prefer R134 over R12. It cost less, is available everywhere and is more environmentally friendly.
Our original GM A6 compressors have been workhorses for years and will work well if maintained and serviced. They are however heavy, the compressor, brackets and mounting hardware add weight to an already nose heavy car and further degrade handling. They are also notorious for leaking; so much so that GM even designed a shield to prevent oil from being slung against the underside of the hood. There is however an upgraded seal kit available to reduce leakage at the clutch shaft.
As Edouard mentioned there is a reproduction A6 compressor sometime called the S6 that is advertised as a direct fit with existing mounting brackets. Made from aluminum it would help reduce some weight. That’s all I know about them, here’s a link.
http://www.s6compressor.com/products.htmlThe Sanden compressor uses less horsepower than the A6. About 6HP at idle compered to 16 hp for the A6. If your struggling with idle issues on a cammed up engine this can make a big difference at idle. These nailhead engines make lots of horsepower and torque at higher RPMs but not so much at idle. I’m guessing here, but probably 80 hp or less, there's already a fair amount of parasitic drag at low rpm. Transmission parts, power steering, alternator and vacuum demand, turning on the AC can make a big difference.
One more thing and I’ll shut up. The Sanden and no doubt the retro A6/S6 will handle higher RPMs than the original A6. Perhaps not a big deal with nailheads as they generate their monster horsepower and torque at lower RPMs.
Sorry for running on so long. Hope it helps.
