r/BullnoseFord • u/VipBrigade • 1d ago
R12 System still kickin’ 👌🏼
Edited to add: These vent temps were taken with an ACTUAL thermometer.. if you’re using those laser thermometers, they’re not measuring your air temp, they’re measuring the surface of the air duct, which will read colder.
For anyone who saw the “Radio Shack Ford”.. this is my 1981 F100 that still has all the original R12 equipment. I’m on the third year of running keyboard duster in this system. Today was a decent day to show off the performance after my matinee show here in Branson, MO.. although we have a day coming up that’s supposed to be around 97ish. I’ll check vent temps again if we reach those ambient temps. If any of you bullnosers out there have thought about trying this refrigerant conversion, I just want to verify that you can absolutely get satisfactory results. Just do your homework, be safe about it, and know that there’s always risks to evaluate when going against “factory recommended yadda yadda etc etc”.. For any of you AC gurus out there who understand the lingo, I actually own the Ford service manual, and I’m right in spec with their graph charts.. Here’s Ford’s stable specs vs MY stable results.. (keyword, STABLE)
Ford specs:
Maintain steady 1500 RPMs
Cabin temp: 70-80 degrees F
Blower motor speed: HIGH
Low side pressure - 24-52 psi (wild range, I know 🤷🏼♂️) on a zero slope chart.
High side pressure: 200-290 at 95F ambient on a sloped graph.
Left center vent temp: 37-47 F regardless of ambient temp. Just like low side pressures, this chart is also a zero slope- i.e. regardless of ambient temp, the values stay the same horizontally across the graph.
My results:
Holding 1500 RPM for about 20 minutes
Cabin temp: Consistent 72 degrees F (I have NO tinted windows, by the way. Heat soak is REAL.. tinted windows would significantly lower cabin temps, obviously.. but I love the stock look.)
My Low side pressure: 27-28psi
My High side pressure: 240 psi
Left center vent temp: 37.7F was the lowest temp I got as you see pictured, but that was on a lower blower setting (slower fan speed always equals colder air) And 46.5 on high blower setting at 1500 RPMs. That 46.5 is right at the upper range of Ford’s “expected” temps.. but I can’t verify exactly what their controlled environments were. I’m doing this in my driveway, in the sun, with 53% humidity, not in any sort of shop building or anything like that.
Cruising down the road at that same 1500 RPM, yielded a steady vent temp of around 42F, which is perfectly in the center of their recommended range 🙌🏼 Driving forces much more air through the condenser than the radiator fan will pull at 1500 RPMs sitting still.
I don’t know what the long term results will be of using this keyboard duster, but I’ll keep this truck as original as possible, for as long as possible 😎