We had a 2nd 911 A/C tech session last Saturday and I finally got around to pumping down and filling the resurrected A/C system on my '76. After locating a leak (flare fitting joint at expansion valve) and replacing a defective high pressure fitting Schraeder valve on the compressor we did the deed. We also converted a Turbo stock system over to R-134a and boosted the fill and added some compressor oil to a Carrera that had already been converted. In the '76 we obtained 50 F vent temp idling in driveway and "putting" around town at 30 mph with 90 F ambient air temp and full sun load. Out at crusing speed (~75 mph) it will freeze one out; I had to increase the temp and turn down the blower. 90 F ambient, ~3-4% grade, 3-4K rpm, 60-65 mph with A/C on full, oil temperature rose to 210 F and stabilized with trombone cooler. Engine has 11 blade fan, new Sanden compressor, NOS engine deck lid condenser, new barrier hoses, new receiver/drier from NAPA, new expansion valve, flushed and cleaned evaporator, better sealing of original blower and I added a 88 CFM muffin fan (12v and .45 amp for $6) behind passenger footwell floorboard to boost air flow across evaporator. Filled the system with ~24 oz. of R-134a; monitered pressures while filling and used a small 110 VAC window box fan to blow air over condenser to obtain better high side pressures while filling. Also have a 300 CFM muffin fan (12v and 2.45 amps for $19.00) to mount on the decklid condenser; there is just enough space to squeeze it in. I will either relay it to come on with the compressor clutch or add a temperature switch on the condenser. Took some digital pictures; I'll try and get them uploaded. Making 911 popcicles in Los Alamos
Jim