R-134a conversion question

["Turbo-T"]

I am familiar with how R-12 is more efficient than R-134a by 20% but here's what I was wondering....

Perhaps someone makes a replacement evaporator and condensor that is suited for R-134a yet designed to work in a G body?

Seems this is the main reason why R-134a in an R-12 system isn't as effiecent as it should be.

If not, is it even remotely possible to get a retrofitted R-134a system to cool like the factory R-12 system did?

 

[toofastforyou]

I did a retrofit this summer on my GN. All I needed to replace was the accumulator dryer because it was the original one (20 years old) and soaked with the oil used for R-12 which is not compatible with the one used with R-134. After replacing it, I did a good vacuum and refilled the system with R-134 and it's been working great since... very cold!...I don't think there's no need to replace anything else...

Claude

 

[Catch]

Just install retro valves, replace accumulator and vacuum the system for about 30 mins. When charging the a/c use 10% less 134a.

 

[justabuickv6]

I replaced everything when I converted over to R134. It never would get colder than 55 at the vent when it was around 95 ambient.

I left everthing as it, with the exception of a vacuum, and installed Freeze 12. It went from 55 to 38.

I love Freeze 12.

 

["Turbo-T"]

Ok, thanx for the input....I was under the assumption since an R-12 system wasn't designed to run on R-134a it would be done properly to just ugrade to a condensor or evaporator that was.

 

[Black Car]

If you can get freeze 12, all you have to do, if the system has no leaks, is pull vac and refill with freeze 12. I did this about 5 years ago and it still works great. At that time freeze 12 was less than $6 a can.
Gary

 

[justabuickv6]

I am not sure what Freeze 12 cost in your area but I pay $7 a can.

 

[83ttypecooled]

Retrofit

Hi,
I was lazy about conversion to 134a back in 2001,had other technical issues to worry about,plus I didn't think I would keep the car. Anyway, I just pumped it down to 29 in Hg,shot an 80% charge of R134a into my system after I fixed the leak it had with a new hose set.I noticed that the new set were barrier hose, which is 134a friendly.My car is still running cool all these years later with that same charge, and is pretty cold, like mid 40s duct temps.Here's a real laugh:I never flushed it, nor did I add any pag or ester oil to the system, so it is still running on mineral oil.The R4 compressor doesn't rattle, and the cooling is sufficient for my preferences.
Also, My TTA was converted when ever, before I owned the car. I guarantee the condenser is stock. I have owned it for three and a half years, never put one ounce or refrigerant in it. It will freeze you out,and is cilder than the Regal.
The bottom line is, R4 compressors are pretty tough,the condensers seem adequate for the new refrigerant,and apparently the old oil provides some sort of lubrication, because both cars still have fully functional AC.
However, don't trust my successes, do the conversion by the book, or close to it. I don't want to feel responsible for the failures that might arise.
Good luck with YOUR SITUATION...

 

[turbodave231]

For most climates, R-134A conversions work good with electrically driven cooling fans. Converting an R-12 car equipped with an engine driven fan is much worse. If you live in Arizona, or Florida, you may not be 100% happy with a TR system performance on R-134a.

The mineral oil does not need to be flushed, and will not move around the system with R-134A. That's why PAG or Ester oil is required (to keep the compressor happy). Replacing the accumulator is a good idea because it will refresh the dissicant (the bag full of moisture absorbing material inside the accumulator).

R-134a finds small leaks easier and gets out quicker because the molecule size is smaller than r-12.

I've done lots of conversions and had good success.

 

[aminga]

If you want to do an R-134a conversion get a set of gauges and do it right. You don't need a new evaporator but you do need a new dryer and orfice tube. If you go by the old guidelines of 80% charge you will not be satisfied with the results. If you get a P-T chart and a set of gauges you will It's a simple as that.

When I converted mine I did a little experiment. After vacuming it down I charged to 80% of the R-12 charge and run it. At 80% charge the high side pressure was 220 psi and the outlet temp was 70degrees. Charging it to the correct pressure (275 for the temp) got the outlet temp down If you charge it with the gauges it will work but the 80% charge is a cheap BS workaround to getting the tools to do it RIGHT.

 

[seeyabye]

Getting the pressures right is crucial to the efficiency of the system. Too little or too much freon and the system will not cool properly. You can buy a cheap set of manifold gauges or take it somewhere. Weigh in the freon to about 85% charge with 134a and you will have no problems. Mine cools down in the 30's with ambient in the 90's. I pulled a good vacuum on it and charged it 4 years ago and it is still going strong. I have not had to add anything since then.