R134A Conversion - ZR-1 Net Registry Forums

Scrrem · 10-04-2010

Thinking about converting my 90 A/C system over to R134a. I have been told that you don't have to change the compressor, it this true? I have been reading that there is a special oil that must be used for the conversion as well. What else needs to be changed for the conversion?
Rich

VetteMed · 10-04-2010

The high/low pressure fittings are different, and all the o-rings need to be changed as well. The pressure switches need to be changed too based on the different properties of R134a. I'm no AC expert, but everyone I've spoken to about the conversion says that it will not cool as well after the conversion because the system was designed for the physical properties of R12... and given the ZR-1's already undersized compressor, that may be asking for poor performance.

Of course, someone around here has probably done the conversion and can give you better info.

ScottZ95ZR1 · 10-04-2010

I have no personal experience with the conversion as of yet but I recently purchased a R12 compressor and when I mentioned the possibility of using it in a R134A application the following was the seller's response to me.

"Although some say the Denso R12 compressors cannot be retrofitted to R134a, they are mistaken. Both the training instructors and engineers I worked with had no problem with retrofitting these compressors. Furthermore, I currently have three friends and customers C4 Corvettes that I personally retrofitted over 6 years ago, still without any problems and blowing cold air. Now what I am going to follow-up with will cause some controversy, but when completing the retrofit, use ester refrigerant oil, not PAG. The reason for this is that any chlorine still in the system can react with PAG oils over a period of time. This is also important if you ever desire to go back to R12".

-=Jeff=- · 10-04-2010

unless the R12 is gone form your system, don't switch. R134a with the smaller compressor and more heat from the LT5, work against it.

now that said, my car has R134a, I think the Compressor may have issues, I have purchased a new parallel flow condenser and will purchase s compressor soon, then next spring I will charge it with R134a and see if that helps.

Another member here posted about a possible Suburban Blower motor to improve flow, but I have not heard anymore regarding it as to the correct year blower to look for

rgfllamas · 10-11-2010

Didn't the 94's and up come with 134 from the factory? Are the compressors, condensors or evaporators different? Do the early cars cool significantly better than the late ones?

Cost of R12 has dropped in the last few years and it's pretty available, why change?

Ken

Scrrem · 10-11-2010

Quote:

Originally Posted by rgfllamas

Didn't the 94's and up come with 134 from the factory? Are the compressors, condensors or evaporators different? Do the early cars cool significantly better than the late ones?

Cost of R12 has dropped in the last few years and it's pretty available, why change?

Ken

Not sure..I thought all C4's had R12.

Unless I'm mistaken, you can't buy R12 without being a licensed AC shop...right? I just wanted to be able to maintain the system myself.
This is the second post I have seen that stated R134A didn't cool as well well as R12...hum, maybe it's not worth it.
Rich

sammy · 10-11-2010

i can only speek about what i did and results . i changed all the o rings and bought the 134 fittings ,low,high. i didnt change the switches. i bought a new accumulator (big round thing up by the radiator).put in 1.8lbs of 134 and 4 extra ounces of oil . that was 3 years ago and the system seems to work fine to me . it keeps me way cool even when i went thru vegas this summer and the temp was 110

10-04-2010	#1
Scrrem Join Date: Feb 2009 Location: Alexandria, Virginia Posts: 1,467	R134A Conversion Thinking about converting my 90 A/C system over to R134a. I have been told that you don't have to change the compressor, it this true? I have been reading that there is a special oil that must be used for the conversion as well. What else needs to be changed for the conversion? Rich __________________ 1990 Bright Red Coupe #608 380 Stroker, Ported Heads/Intake/Housings/TB Haibeck Secondary Delete Chip / Pete's Cams George Braml Intake / FIC Injectors Coated SW Headers / Corsa Bill Boudreau B/B ZF6 / Viper 4.10 gears Ron Davis Radiator Pioneer AVIC-Z140BH NAV Fikse FM5's 285 / 335 / C6 Brakes WAZOO Member

10-04-2010	#2
VetteMed Join Date: Mar 2009 Location: Orlando, FL Posts: 1,828	Re: R134A Conversion The high/low pressure fittings are different, and all the o-rings need to be changed as well. The pressure switches need to be changed too based on the different properties of R134a. I'm no AC expert, but everyone I've spoken to about the conversion says that it will not cool as well after the conversion because the system was designed for the physical properties of R12... and given the ZR-1's already undersized compressor, that may be asking for poor performance. Of course, someone around here has probably done the conversion and can give you better info.

10-04-2010	#3
ScottZ95ZR1 Join Date: Mar 2008 Location: Pendleton, IN Posts: 659	Re: R134A Conversion I have no personal experience with the conversion as of yet but I recently purchased a R12 compressor and when I mentioned the possibility of using it in a R134A application the following was the seller's response to me. "Although some say the Denso R12 compressors cannot be retrofitted to R134a, they are mistaken. Both the training instructors and engineers I worked with had no problem with retrofitting these compressors. Furthermore, I currently have three friends and customers C4 Corvettes that I personally retrofitted over 6 years ago, still without any problems and blowing cold air. Now what I am going to follow-up with will cause some controversy, but when completing the retrofit, use ester refrigerant oil, not PAG. The reason for this is that any chlorine still in the system can react with PAG oils over a period of time. This is also important if you ever desire to go back to R12".

10-04-2010	#4
-=Jeff=- Join Date: Jul 2007 Location: Bartlett, IL Posts: 7,169	Re: R134A Conversion unless the R12 is gone form your system, don't switch. R134a with the smaller compressor and more heat from the LT5, work against it. now that said, my car has R134a, I think the Compressor may have issues, I have purchased a new parallel flow condenser and will purchase s compressor soon, then next spring I will charge it with R134a and see if that helps. Another member here posted about a possible Suburban Blower motor to improve flow, but I have not heard anymore regarding it as to the correct year blower to look for __________________ 1990 Corvette ZR-1 #1051 Watson Headers (2" Primary) - Flowmaster Cats - Borla Catback Late Model IH - Plenum Coilovers - 4.10s Custom Interior NCM Lifetime Member #978

10-11-2010	#5
rgfllamas Join Date: Aug 2008 Location: Palm City, Fl Posts: 32	Re: R134A Conversion Didn't the 94's and up come with 134 from the factory? Are the compressors, condensors or evaporators different? Do the early cars cool significantly better than the late ones? Cost of R12 has dropped in the last few years and it's pretty available, why change? Ken

10-11-2010	#7
sammy Join Date: Jun 2010 Location: back in lone pine Posts: 591	Re: R134A Conversion i can only speek about what i did and results . i changed all the o rings and bought the 134 fittings ,low,high. i didnt change the switches. i bought a new accumulator (big round thing up by the radiator).put in 1.8lbs of 134 and 4 extra ounces of oil . that was 3 years ago and the system seems to work fine to me . it keeps me way cool even when i went thru vegas this summer and the temp was 110