Several years ago I added a second evaporator mounted under the co-pilot seat. (Credit to the late Jim Anstette for the idea.)
I put a cookie sheet (baking pan?) on the floor to catch the condensed moisture and lead it down through a tube in the floor. I bought (years ago) a
rear A/C - heater unit from an ambulance on e-bay for parts. This unit is a bit bulky which made connecting the lines in the limited space a bit
tedious. The dual squirrel-cage blowers are mounted on the back of the seat pedestal, tucked neatly between the pedestal and the dinette seat back.
(My dinette is raised ~5" giving a little more room.) A couple of computer fan grilles keep fingers and debris out of the fans as they blow into the
seat pedestal. Air travels forward through the evaporator which is located just ahead of the seat pivot post. The space forward of that (about 8" or
so) serves as a plenum chamber (and a place to lay a few beverage cans for quick cooling). Cold air discharges through a couple of vents on the front
left side of the pedestal, which can be aimed towards the driver or back towards the couch. A couple pieces of old vacuum cleaner hose (!) exit the
front right corner of the pedestal, curve upward where they enter the armrest and discharge through another adjustable dash-type grille. If one needs
a LOT of cool air (and the co-pilot is wearing insulated boots) we can just open the pedestal storage door and dump a huge blast of cold air. A fan
switch is also mounted on the co-pilot's armrest.
The refrigerant lines were easier than expected. A couple of tee fittings near the receiver-dryer feed a pair of hoses running rearward outboard of
the A/C compressor, then up through the floor to connect to the evaporator. Of course the compressor is still controlled by the original dash air
thermoswitch, so the dash air must be on for things to work. It works about as well (or poorly) as it ever did. No special refrigerant valves or
controls were needed. Dura-Cool (thanks Emery!) does the work. The GMC's A6 compressor is about the most powerful ever made for a passenger car
(45,000 btu/hr), so it has no trouble pumping the refrigerant. I figure it's about as powerful as my home's central A/C system.
Does it work? Does it ever! Puts out at least as much air at a MUCH lower temperature than the original dash air. We are COOL! Best modification I
ever did.
HTH,
Rick Staples
--
Rick Staples, '75 Eleganza, Johnstown, CO
"Advice is a dangerous gift, even from the Wise to the Wise, and all paths may run ill." -Tolkien
