Air Conditioning Upgrade
10-13-2009, 05:39 PM
#17
Race Car
Conversion to 134 should not cost more than $150. Evacuate the system of R12, refill with R134. Thats it. Do this first. Then start to see where your problem is, if there is one at all. This will offer you years of service. Don't do the hose/ expansion valve/compressor/dryer replacement. It is not needed at all in the conversion. These things will continue to work as intended regardless of freon type. Only the oil type is specific to the freon. Even that is a non issue now that oil compatible with any freon is available. (I like BG oil/dye charge). Anything else is a waste of time and money.
10-13-2009, 06:04 PM
#18
Rennlist Member
Did the full Griffith's system....new hoses, compressor, evap, receiver/dryer, expansion valve, front and rear condenser, two additional condensers with fans in the left rear wheel well, center vent, and variable fan controller...great performance in Florida...29-35 out of the vents...completely satisifed...went the entire summer without sweating in my car...interior temps stabilized after about 10 minitues in the low to mid 70s on the 95+ degree, high humidity days and sub 70 degrees interior temps when low 90s or less. Ran $4500 parts and labor...had a Porsche mechanic at the Destin dealership install it (15 hours labor) who had 20+ years exp and had installed several of the Griffith's system. He along with an independent Porsche mech in Pensacola both said it was hands down the best AC system they had ever installed.
Also installed a BMW 99C temp switch in the right front oil cooler to have it come on earlier to aid in engine cooling and the Pelican Oil cooler scoop for the right front fender. No problems with overheating even in up to two hours of stop and go traffic with the AC on max.
I decided to do replace everything rather than piecemealing the fixes and being unsatisfied. Good luck!
Also installed a BMW 99C temp switch in the right front oil cooler to have it come on earlier to aid in engine cooling and the Pelican Oil cooler scoop for the right front fender. No problems with overheating even in up to two hours of stop and go traffic with the AC on max.
I decided to do replace everything rather than piecemealing the fixes and being unsatisfied. Good luck!
10-13-2009, 10:41 PM
#19
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Great feedback guys.
I know I have to replace the compressor, so that requires receiver/dryer replacement. Since I don't know about leaks yet, but know the a/c worked when the compressor worked when it was charged, then I could just move on to to evacuating the system and refill with R134 or try freeze12, and see how things go from there.
If that doesn't work then I can go on to the full monty system swap.
What device or where do I get something to evacuate the system, or will I have to have someone do this for me. Any idea of cost of this? I heard the refill system for R134 is a inexpensive kit, but what is required to evacuate the system?
I know I have to replace the compressor, so that requires receiver/dryer replacement. Since I don't know about leaks yet, but know the a/c worked when the compressor worked when it was charged, then I could just move on to to evacuating the system and refill with R134 or try freeze12, and see how things go from there.
If that doesn't work then I can go on to the full monty system swap.
What device or where do I get something to evacuate the system, or will I have to have someone do this for me. Any idea of cost of this? I heard the refill system for R134 is a inexpensive kit, but what is required to evacuate the system?
10-13-2009, 11:37 PM
#20
Drifting
Did the full Griffith's system....new hoses, compressor, evap, receiver/dryer, expansion valve, front and rear condenser, two additional condensers with fans in the left rear wheel well, center vent, and variable fan controller...great performance in Florida...29-35 out of the vents...completely satisifed...went the entire summer without sweating in my car...interior temps stabilized after about 10 minitues in the low to mid 70s on the 95+ degree, high humidity days and sub 70 degrees interior temps when low 90s or less. Ran $4500 parts and labor...had a Porsche mechanic at the Destin dealership install it (15 hours labor) who had 20+ years exp and had installed several of the Griffith's system. He along with an independent Porsche mech in Pensacola both said it was hands down the best AC system they had ever installed.
Also installed a BMW 99C temp switch in the right front oil cooler to have it come on earlier to aid in engine cooling and the Pelican Oil cooler scoop for the right front fender. No problems with overheating even in up to two hours of stop and go traffic with the AC on max.
I decided to do replace everything rather than piecemealing the fixes and being unsatisfied. Good luck!
Also installed a BMW 99C temp switch in the right front oil cooler to have it come on earlier to aid in engine cooling and the Pelican Oil cooler scoop for the right front fender. No problems with overheating even in up to two hours of stop and go traffic with the AC on max.
I decided to do replace everything rather than piecemealing the fixes and being unsatisfied. Good luck!
You probably need a new thermometer.
10-14-2009, 09:28 AM
#21
Rennlist Member
I have used three different thermometers all indicating within 2 degrees of each other. I have found that turning the fan (variable fan controller) and temp down to about 60% or so works best as far as achieving the lowest temps. One problem I occasionally have is that my rear plastic window (cab) becomes hard to see out because of the condensation build up as well as part of the passenger window and part of the driver window.
The numbers are correct because after about 45 minutes in high humidity days, as you suggest, I do get condenser freezing and reduced air volume due to the evaporator freezing. I have to turn the temp switch to min cold and the fan to high for about 5 minutes to melt the ice indicated by increased blower volume and increased output temp to the 40s all while the interior stays nice and chilly. After that it is back to the normal settings and 29-35 out of the vents. I now have learned to set my temp selector to about 45% of max cold and that seems to keep it from freezing for well over an hour with interior temps in the high 60s/low 70s.
I would like to know if there is any way to modify the intake system to recirculate from the interior as you suggest that would keep the condenser from freezing in high humidity days. It is a minor pain to have to melt the ice occasionally (have to reach all the way down to the ***** and turn them!) but compared to the last few summers in south Florida and the panhandle sweating like crazy with insufficient cool air flow, it's a small price to pay.
The numbers are correct because after about 45 minutes in high humidity days, as you suggest, I do get condenser freezing and reduced air volume due to the evaporator freezing. I have to turn the temp switch to min cold and the fan to high for about 5 minutes to melt the ice indicated by increased blower volume and increased output temp to the 40s all while the interior stays nice and chilly. After that it is back to the normal settings and 29-35 out of the vents. I now have learned to set my temp selector to about 45% of max cold and that seems to keep it from freezing for well over an hour with interior temps in the high 60s/low 70s.
I would like to know if there is any way to modify the intake system to recirculate from the interior as you suggest that would keep the condenser from freezing in high humidity days. It is a minor pain to have to melt the ice occasionally (have to reach all the way down to the ***** and turn them!) but compared to the last few summers in south Florida and the panhandle sweating like crazy with insufficient cool air flow, it's a small price to pay.
10-14-2009, 01:42 PM
#22
I haddah Google dat
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Great feedback guys.
I know I have to replace the compressor, so that requires receiver/dryer replacement. Since I don't know about leaks yet, but know the a/c worked when the compressor worked when it was charged, then I could just move on to to evacuating the system and refill with R134 or try freeze12, and see how things go from there.
If that doesn't work then I can go on to the full monty system swap.
What device or where do I get something to evacuate the system, or will I have to have someone do this for me. Any idea of cost of this? I heard the refill system for R134 is a inexpensive kit, but what is required to evacuate the system?
I know I have to replace the compressor, so that requires receiver/dryer replacement. Since I don't know about leaks yet, but know the a/c worked when the compressor worked when it was charged, then I could just move on to to evacuating the system and refill with R134 or try freeze12, and see how things go from there.
If that doesn't work then I can go on to the full monty system swap.
What device or where do I get something to evacuate the system, or will I have to have someone do this for me. Any idea of cost of this? I heard the refill system for R134 is a inexpensive kit, but what is required to evacuate the system?
SOME people I know (who shall go un-named) figure that since the system is compromised anyway, and there is no pressure in the system, there is no need to recover the old freon, so it's ok to just go ahead and skip the recovery step. In that case, you can buy a Robinaire vacuum pump, or go the El Cheapo route and buy an electrical 1.5 hp vacuum pump from Harbor Freight. Either way, buy new compressor oil. You can get it locally at Graingers, or you can order it via mail from any good supply house.
Last edited by rusnak; 03-05-2010 at 12:07 AM.
10-14-2009, 08:52 PM
#23
Drifting
I have used three different thermometers all indicating within 2 degrees of each other. I have found that turning the fan (variable fan controller) and temp down to about 60% or so works best as far as achieving the lowest temps. One problem I occasionally have is that my rear plastic window (cab) becomes hard to see out because of the condensation build up as well as part of the passenger window and part of the driver window.
The numbers are correct because after about 45 minutes in high humidity days, as you suggest, I do get condenser freezing and reduced air volume due to the evaporator freezing. I have to turn the temp switch to min cold and the fan to high for about 5 minutes to melt the ice indicated by increased blower volume and increased output temp to the 40s all while the interior stays nice and chilly. After that it is back to the normal settings and 29-35 out of the vents. I now have learned to set my temp selector to about 45% of max cold and that seems to keep it from freezing for well over an hour with interior temps in the high 60s/low 70s.
I would like to know if there is any way to modify the intake system to recirculate from the interior as you suggest that would keep the condenser from freezing in high humidity days. It is a minor pain to have to melt the ice occasionally (have to reach all the way down to the ***** and turn them!) but compared to the last few summers in south Florida and the panhandle sweating like crazy with insufficient cool air flow, it's a small price to pay.
The numbers are correct because after about 45 minutes in high humidity days, as you suggest, I do get condenser freezing and reduced air volume due to the evaporator freezing. I have to turn the temp switch to min cold and the fan to high for about 5 minutes to melt the ice indicated by increased blower volume and increased output temp to the 40s all while the interior stays nice and chilly. After that it is back to the normal settings and 29-35 out of the vents. I now have learned to set my temp selector to about 45% of max cold and that seems to keep it from freezing for well over an hour with interior temps in the high 60s/low 70s.
I would like to know if there is any way to modify the intake system to recirculate from the interior as you suggest that would keep the condenser from freezing in high humidity days. It is a minor pain to have to melt the ice occasionally (have to reach all the way down to the ***** and turn them!) but compared to the last few summers in south Florida and the panhandle sweating like crazy with insufficient cool air flow, it's a small price to pay.
Probably the best procedure is to set the control to the coldest setting and then move the sensing element closer and closer to the evaporator surface until the compressor clutch circuit opens just a tad above the evaporator core reaching 34F.
10-14-2009, 10:25 PM
#24
2nd Gear
It's October! Roll the windows down and drive it like it was suppose to be driven. Worry about the AC repairs over the winter months.
1976 911S Targa...............No A/C
1976 911S Targa...............No A/C
10-14-2009, 11:35 PM
#26
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More good comments and information.
I believe I'm on the right track now. I have to replace the compressor for sure, it is slinging oil (going bad) and the system is down on R12 after leaking the last 2 years. I may replace the dryer/receiver when I do the compressor, just because it seems to be a very recommended thing to do and not a very expensive part. Then fill with R134 and try it out.
I have a few parts stores nearby and I will check to see if they rent the vacuum pumps. I really don't want to buy one just for this one project.
For sure this is the time of year I can enjoy the car, top off and not worry about the a/c, but I will get it working...I don't like it when something doesn't work...
I believe I'm on the right track now. I have to replace the compressor for sure, it is slinging oil (going bad) and the system is down on R12 after leaking the last 2 years. I may replace the dryer/receiver when I do the compressor, just because it seems to be a very recommended thing to do and not a very expensive part. Then fill with R134 and try it out.
I have a few parts stores nearby and I will check to see if they rent the vacuum pumps. I really don't want to buy one just for this one project.
For sure this is the time of year I can enjoy the car, top off and not worry about the a/c, but I will get it working...I don't like it when something doesn't work...
10-15-2009, 08:07 AM
#27
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Shoot me an email if you need help & advice at mthomas58@comcast.net. I have the vacuum pump pictured above and can help you with flushing, evac and charging with 134a. I've done quite a bit of A/C work on my car. Check out my posts on Pelican under mthomas58. I'm next door to you in Roswell.
http://forums.pelicanparts.com/porsc...-tomorrow.html
Mark
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87 911 Coupe
Granite Green Metallic
http://forums.pelicanparts.com/porsc...-tomorrow.html
Mark
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87 911 Coupe
Granite Green Metallic
Last edited by mthomas44; 10-15-2009 at 08:55 AM.
10-15-2009, 03:18 PM
#28
I haddah Google dat
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IIRC, Mark you bought a suction pump and did a comprehensive flush. That was a very nice thread, and good work. JFairman is knowledgeable about AC work on these older Porsches as well.
Ha, I just re-read the first page of that thread. Mark, I think you convinced me to buy the Robinaire pump. It is worth every penny, and I'm glad that I did!
My own $.02 is that you'd be a goldmine of info and help on the 134a conversion.
Ha, I just re-read the first page of that thread. Mark, I think you convinced me to buy the Robinaire pump. It is worth every penny, and I'm glad that I did!
My own $.02 is that you'd be a goldmine of info and help on the 134a conversion.
10-15-2009, 09:15 PM
#29
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IIRC, Mark you bought a suction pump and did a comprehensive flush. That was a very nice thread, and good work. JFairman is knowledgeable about AC work on these older Porsches as well.
Ha, I just re-read the first page of that thread. Mark, I think you convinced me to buy the Robinaire pump. It is worth every penny, and I'm glad that I did!
My own $.02 is that you'd be a goldmine of info and help on the 134a conversion.
Ha, I just re-read the first page of that thread. Mark, I think you convinced me to buy the Robinaire pump. It is worth every penny, and I'm glad that I did!
My own $.02 is that you'd be a goldmine of info and help on the 134a conversion.
Great investment....I've used is several time for myself, Porsche friends and neighbors.
Getting the A/C working properly and completing several performance upgrades are among the most satisfying projects I've done.
Last edited by mthomas44; 10-16-2009 at 12:01 AM.
10-15-2009, 11:24 PM
#30
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Thanks for all of the information.
After referring to the in-depth posts by Mark on the whole hog project on Pelican, I'm a little concerned with this....I'm hoping it isn't over my head. That was a great thread. You couldn't ask for more pictures and expert information. So many details...
Mark I appreciate the offer on the pump and will contact you when I know I will have the compressor replaced, receiver/ dryer installed and ready to evacuate and charge.
Hopefully we will have a few more warm spells over the next few weeks.
Many thanks again.
After referring to the in-depth posts by Mark on the whole hog project on Pelican, I'm a little concerned with this....I'm hoping it isn't over my head. That was a great thread. You couldn't ask for more pictures and expert information. So many details...
Mark I appreciate the offer on the pump and will contact you when I know I will have the compressor replaced, receiver/ dryer installed and ready to evacuate and charge.
Hopefully we will have a few more warm spells over the next few weeks.
Many thanks again.