I've taken 2 of my old wagons, (88 124 and 85 123) and simply evacuated the systems, swapped out to 134 exp valves, replaced the driers and o-rings and blown in 134. With ester100 of course. I charge them a little different tho', start at 50% which is about 12 OZ and slowly blow in the rest looking for the lowest temp at the center vent, windows closed, recirc door closed and car fully warmed up. The 88 wagon in a shop that was about 85 deg F at the time worked itself to 44 deg F and Tom just took it to Texas and said it maintained 44 to 48 the entire trip. The 85 made it to 50 and maintains it well except sitting in traffic if the temp is over 90, it'll get into the high 50's then.
No changed were made to the basic system other than expansion valves. I did however seal the condenser to the radiator as well as I could.
On a 'nother note, I converted a 92 Lexus ls400 today (and guess what, it needed a evap) and it made it down to 48 inside the shop and today it was 95 deg in there when I charged it.
One BIG issue I've seen over and over are oil flooded systems and 134 systems seem to be particually sensitive to this problem. 2 OZ too much oil can raise output temps 15 deg's depending on the size of the system. Both of the wagons already had the red pressure switches for the aux fans so they were left alone.
134 aint a straight up replacement for good old 12 but, it'll do a decent job provided you run a 134 expansion valve, be sure not to oil flood the system and ignore that damn sight glass while charging. (I've noticed that around 2600 rpm the glass will clear on the ones I've charged by temp and paid attention to.)
One trick I use as well is superheat, put a temp probe on the suction line right at the expansion valve and charge it untill the the temp at that point is about 38F, the high side will be in the 240F zone at that point. Dont forget the old rule of thumb, on fresh air intake output temps that are 30 deg's lower are acceptable. And I've seen some that would barely do 20.
I'd run from the off the wall stuff due to too damn many potential problems with flammability and performance over the long haul. And a quick remark to the guy who feels shops overcharge for r12, bought a reclaimer lately? They aint cheap.
Project Smoker, '87 603 powered wagon
Hauler, 96 CTD can you say torque?
Toy 73 Cougar xr7 convertible
Acme Automotive Inc.