92RS4US

Has anybody done this conversion to their A/C system? I did it on my 87 RS and all I did was add the new fittings and evac and charge the system with R134a. It worked but the compressor was bad so I changed it and recharged it with R134a again. It worked good and the fan came on with the A/C. Has anybody done this differently?

Fast355

iTrader: (2)

You will buying another compressor very soon.

nickfrmtx89

why? i'm gonna have to do it to my 92 RS here soon before spring comes around.

92RS4US

the original compressor worked fine it just started leaking from everywhere. That was when I recharged it with R-12. I decided to convert to R-134a because I could get that refrigerant cheaper. It's been a long time since I did that so I was wondering what others have done. Everybody I had talked to seemed to make such a big deal of it, I thought it wasn't a big deal at all.

TransAmGTA88

I switched my over with no problem at all, just bought a conversion kit from auto zone.

91phoenix

iTrader: (5)

When I learned about doing the conversion I was told that the 134A will make a weak compressor quit sooner due to higher pressures. The hoses will usaully work fine but if you get new hoses make sure they are designed for 134A. It is a smaller molecule and can leak through regular hoses. With older hoses they have absorbed some oil etc. so they do not leak. I was also told it was a good idea to replace the expansion valve. I do not know personally about the hoses but do know that a proper expansion valve could give a couple of degrees colder air.

eseibel67

Third gens do not use expansion valave, they use orifice tube. And yes, you should replace it.

91phoenix

iTrader: (5)

Thank you for correcting me. That is what I meant but got the name wrong.

92RS4US

Well I finished my retrofit yesterday. New compressor, added the fittings, evac and recharged the system and now I got ice cold A/C. 45 degrees sitting in my shop at 100* ambient temp with no air flow across the condenser.

91phoenix

iTrader: (5)

As long as you got the proper amount of oil added to the compressor if it wasn't already added then you should be good as long as there no leaks anywhere. (Should have shown up on evac.) Most new compressors are built to handle 134a now so that should not be an issue.
I have found that going down the road 45 degrees is still not as cold as possible but usually cold enough. Yes I read you said sitting and not moving.

abray1

freeze 12 is the way to go.

92RS4US

I agree I've seen some systems run at 32* and freeze the evaporator. In AZ when its over 100* and inside the car its 50* thats good enough.

fasteddi

iTrader: (2)

Anything under 32 degrees on that evap and youll freeze it up and will flood the Comp. And keep in mind if a coil is 32 degrees youll never get the air to be 32 degrees. So if the coil is 32, depending on the Evap, you air coming out of the coil will be 42-44 degrees. If you freeze it up your gonna have a whole bunch of issues exspecially since R134 is not a good Ref for temps that low. You always have to keep in mind that a Evap. is engineered for a certain TD(temp difference) accross the coil.

There is no drop in for R12 or any other ref, without doing work to the system. The Temp/Pressure relationship is so much different. And since they havent made any Virgin R12 since Dec 1995(you probley never find it)

So just use the conversion packages they make and make sure you charge it as its said to and install the proper seals and oil(mineral oil is not what R134 likes to mix with). Esteroils such as POE is for HCFC Refrigerents such as R134. Too much R134 and youll be overcharged and have crappy superheat(thats so the comp doesnt get flooded, and eventually break it) Too little Ref and you have no subcooling and thats just starving the evap. Fixed oriface systems are critically charged so weigh it in, and hope that the cheep guage or scale they sell is some what accutate.

Not sure how many ppl have R22 in there home AC units but be aware that the price of that stuff is skyrocketing right now as its production was cut in half this year. And by 2020 it will be out of production. This ticks me off as a lbs of R22 went from 20-25 bucks to almost 50 bucks. So when you pay a tech to fix it and they say it cost 75 bucks to add REF youll know why.

I just saw this post and figured Id add a little info about MVAC and HVAC in general. Sorry if its not really helpful. Its not every day I see a post on here about what I actually do for a job.

Fast355

iTrader: (2)

The system cycles when the pressure drops to low, so it is not a problem to get the evaporator cooler than 32*F. When the compressor cycles off the temperature will rise above 32*F and melt the ice out of the evaporator. I have seen the air temperature in my Ram get down to 29*F discharge air before the temperature probe in the evaporator cycles the compressor. The liquid line from the orifice to the evaporator and the suction line from the accumulator both get a light layer of frost on them. The second the compressor cycles off, the frost dissapears. HC is a drop-in for R12 if someone feels the need to go that path. Honestly with the efficiency increase over R134a it is worth it to me.

On the 97 Express running R134a, I can get a sub freezing vent temp when the compressor is cycled on, but the low side has to pull down to about 22 psi, which it can down on the interstate with good airflow over the condensor. The only downside is even with an upgraded engine cooling fan, fan clutch, sealed gap between the radiator and condensor, at idle it will only pull down to 50 psi with dual evaporators. That is good for ~60*F vent temps in 105*F weather.

However that being said, with HC refrigerant, the high side pressure stays about the same as with R134a, but the cooling capacity at idle nearly doubles. I only have to pull down to 40 psi to get discharge air in the 28*F range. At idle with the same 50 psi, I get 40*F discharge temps. The pulldown is also roughly 2x as quick. You cannot even put it in reverse, back out of the driveway before the a/c is blowing ice cold.

Dilys95

You will buying another compressor very soon.

Reid Fleming

iTrader: (2)

You'd think the evap would freeze up, but it doesn't. The cycling that our R4 compressors does at stock low pressure cut off points (26 psi) keeps any ice build up to a minimum. And when it cycles off, it won't come back on until 46 psi. And the ice will be long gone by the time it gets to 46 psi.

My car cycles off at 30° duct temps. Evap is running around 20° at that point. I've driven from Houston to Austin and back (2 hours each way) and no problems with reduced air flow/freezing. The only thing that freezes is me!

I'm actually running 55% R-22 in my car. Gives it a wicked boost of performance. Yet it matches the pressure/temp of R-12 for the most part due to the other 45% of R-142b and R-600a. I do get colder temps at any given psi compared to R-12 though. Works great with the same mineral oil that R-12 used as well.

The temp/pressure during the initial pull down really is amazing isn't it? At startup on a hot day, the refrigerant will be ambient temp. Around 100 psi. Yet by the time it's only gone down to 90 psi, it's giving the same cooling that R-134a would be at 70 psi. So you get a fast blast of cold air right away. And it gets colder faster than R-134a at the same time, since R-134a is an inefficient and high pressure refrigerant.

Fast355 and I get about 1.5-2 degree temp drops per second upon turning on the A/C. And that's in the summer time. By the time you've had the A/C on for 10 seconds, you've already dropped the air temps by 15-20°F.

I was just looking at an old post of mine from the summertime. Houston TX, 102°F, 37% humidity, 76°F dew points. And I was getting 34° blowing out the ducts driving in the city. Arizona gets the high temperatures, but doesn't have to deal with the humid weather that Texas has. (Humid air is harder to shed heat from the condenser to the ambient surrounding air. Just as the human body has a harder time shedding heat to the ambient in humid weather compared to dry climates)

Hate to say it. But it's true. Mineral oil and R-134a is a bad combo. And even if you flushed the old mineral oil out, you still run into R-134a reacting nasty with the chlorine left behind in the hoses. (Extremely hard to flush out chlorine deposits)

Reid Fleming

iTrader: (2)

Here's some old video I took in June.

http://smg.photobucket.com/albums/v2...ofrostdemo.flv

Not uncommon to see a trail of water for several feet behind me where I've just driven, upon getting home.

http://smg.photobucket.com/albums/v2...stdraining.flv

After 15 minutes of being parked.

fasteddi

iTrader: (2)

There is no Drop in Replacement for R12 period. If you just take out the old R12 and put R134a in you will have problems eventually. Its a "drop in" if you put in POE oil and change out the fittings as the temp/pressure relationship is different. If you want I'll link up the info on it. But mineral oil does not mix with R134a and eventually your compressor will go bad from the oil not returning back to the comp. And hope that your evap doesnt get oil logged as if that happends, you might as well throw it away.

Ill just add this though that I tell everyone. If you would braze in lineset and not sweep nitrogen you will have a burn out eventually which is a PITA to fix. Its the same with the POE(ester oils) not being dumped into the R134a system. Im not sure if the 134a kits they sell have the oil already mixed in the REF so its not virgin anymore but I guarentte in 5 years of abuse your comp will die.

Really you should be able to get 80% of the old mineral oil out of the system before doing the conversion to R134a and POE oil to match. But People get away without doing this but its not what I would ever reccomend.
Im not a specialist at MVAC but in Hvac/R is is a huge no no to mix any Ref with a oil that is not ment to be with it. Weather it be R22, R123, R134a or any R12 that is left.

CFC=Mineral oil period
HFC=Mineral oil or AB
HCFC=POE or ester based oils

As for the evap TD, amazing that those comps run like they do with evap temps so low. MVAC isnt my main thing, does anyone know what the compressor actually is?? A recep, scroll, screw?? I would Think it is a recip comp.

Im also woundering what blend you have in your car Rick Flem? Whats the blend called?? Its amazing anymore that every REF is a blend of mixed Ref's. And how bad some of the temp glides are. I work with Ref MP39 all the time and that is a picky ref to charge and evacuate due to its glide. This is what I had in my camaro back in the day when I didnt know what I was doing, It worked though for 4 years till I had a burn out on the compressor from not sweeping the lines when I brazed them. A acid burnout is a mess, and I actually had rigid copper lineset all throughout my camaros A/C system...

fasteddi

iTrader: (2)

You relize 22psi is 24 degrees temp, thats is cold man. My car had a modded MP39 ref system and was putting out 45 degree discharge air and it cooled fast. Although it was over sized 600btu(1/2 ton which was way big for a car) I even rigged up a nice TXV so my set up was way far from what the factory made but it worked well for awhile.

Its not the temp that is what cools the car as fast as the removal of the latent heat. The bigger TD you have the more moisture that you will get rid of. Im curious to see what your subcooling and superheat numbers are along with the pressures of the High side/low side, and your discharge wet bulb temp. The slower the evap fan is the more moisture you will remove making it feel colder then it really is.

fasteddi

iTrader: (2)

Read through this if you wana learn more. I mainly work with Copeland but even tecum. has good info.

http://www.tecumseh.com/en/canada/li...f%20R134a.ashx

The reason I say add fittings and such for the increase in pressure is because:
a normal day 90*plus heat of compression=120* R12 has 158psig R134a has 171psig.
On a extreme day the 158* R12 x 1.30= 205 head 171* R134ax1.30=223psig. So there is a good difference in head pressure and if your condenser is a little dirty look to see those #' go much higher and the larger the difference past the balance point the greater the difference in pressures. God forbid you get a leak and dont know it, and that comp will be toast really fast from the REf not cooling it as it should, your discharge temps will be so hot! No subcooling and mass superheat.

Just my 2 cents..

91rs1022

iTrader: (3)

409A is a drop in for an r12 system. We use it everyday at work on old r12 bulk tanks, tractors, cars. You can add it even if you still have freon in the system. Works good.

torque_is_good

i had a bad compressor and the system was disconnected and open. I installed a new compressor, accumulator and orifice and replaced one hose.......no problems 14 months and going strong in FL

Krik

iTrader: (4)

R12 is a superior product. I don't know why anyone would ever switch to 134a. You can still buy it at Pep Boys for about $50 per can. You need a licence to buy it. You can take a test online to get your license online.

This information was true a couple of years ago, but I doubt if it has changed.

fasteddi

iTrader: (2)

I have a EPA universal licence, and they havent produced R12 since December 1995. Look it up! R12 is great but cost alot IMO.

If its under a 20lbs jug tank, you dont need a EPA licence. That why they sell Ref at auto zone or walmart

This crap is a rip I think as R12 is great but wow 50 bucks for less then a lbs http://www.ebay.com/itm/Johnsens-Fre...eeb496&vxp=mtr. And Freeze 12 is not real R12 since it has no CFC's in it but is practical for a fill up on cool juice.

Heres some info on Freeze 12:

• What is the EPA status of Freeze 12 ? Freeze 12 is EPA acceptable subject to use conditions for mobile vehicle air conditioning.
  
  
  
  
  
  Are Freeze 12 and Freezone the same? The two are similar in formulation, but are two different products. TCC only markets Freeze 12.
  
  
  
  
  
  Is Freeze 12 military approved or approved by TARDAC or MEEP? No, it is not.
  
  
  
  
  
  How much will Freeze 12 cost? It will be priced less than R-12 was in 1995.
  
  
  
  
  What is involved in a retrofit to Freeze 12 ? The law requires that the existing refrigerant in the system be evacuated and unique fittings and a label be installed with any replacement refrigerant. Also, if the A/C system being converted is equipped with a High Pressure Relief Valve, a High Pressure Cutout Switch must be installed in accordance with EPA SNAP regulations. Use of Freeze 12 does not require that the lubricant or other components be changed.
  
  
  
  
  
  What are the requirements for recovery equipment with Freeze 12 ? The EPA requires that recovery of Freeze 12 must be done with a dedicated recovery unit. TCC offers a competitively priced unit for this purpose.
  
  
  
  
  If Freeze 12 is recovered out of a system what should be done with it? TCC has a return cylinder program for the recovered material to be sent back to us.
  
  
  
  What is the warranty of a new compressor using Freeze 12 ? At this time some evaluations are taking place which will determine the warranty situation of a new compressor using Freeze 12. Currently there are no new compressor warranty endorsements for Freeze 12. We expect this to change as there were no new compressor warranties in the beginning for R-134a retrofits and now most compressor manufacturers offer them.
• Why should I retrofit an R-12 system with Freeze 12 instead of R-134a?

3. Freeze 12 works with the existing mineral oil and does not require lubricant replacement as R-134a does.

• Why should I buy Freeze 12 instead of one of the other alternatives?

• Can I use Freeze 12 in non-automotive applications?
  
  
  
  Because of the license agreement on this patented product, TCC can only sell it for automotive use. TCC is Technical Chemical Co. and is the manufacturer of Johnsen Products/Freeze 12
  
  

Krik

iTrader: (4)

You can get a license online for $20. You can buy R12 on ebay, or at Pep boys (I have heard that o-reilys sells it too) for about $50.

R12 is a superior product to 134a. If I had the money I would pay/bribe someone to convert my truck to it. Oklahoma is as hot as the Devils underwear.

fasteddi

iTrader: (2)

Why would you buy a licence if you dont need it just go to autozone, walmart, or sams club. Under 20lbs requires NO licence(unless its the real deal CFC's"R12). Just buy the Freeze 12 and call it a day, since that requires NO licence

http://www.epatest.com/store/product...ification-card You mean a card like this...LOL whatever gets ppl the Ref is cool

Just set set up your system to run 410a then youll be nice and cold...

Krik

iTrader: (4)

Why would I spend the money? Why would I get the license? Because its worth it! The measure of an air conditioner is .... you know the answer?... how cold it can get. R12 is a superior product to R134a or Freeze 12. I understand that its cost prohibitive, I get it. That said, if you can afford it, i would never ever switch over to anything else.

fasteddi

iTrader: (2)

I know man, you said it 3 times now. Ill nicely leave this thread.

I love R12 too but anymore its just outdated, there is alot of REF's out there I can think of about 50 of them off the top of my head. Gotta love blends. R12 was the best Ref along with R123 and others I totally agree on that. And I was giving you props for getting a card for 20 bucks. I had to pay 100 bucks for a EPA test and thank god I passed it because if I didn't I was out 100 bucks. But its a universal licence so I can work on class 1,2,3 and Buy/Sell all REF's except for ammonia and old school refs that are in big boy stuff.

Didnt mean to make you upset or anything man, just taking, thats all.

Krik

iTrader: (4)

no love lost man. I thought you were trying to convince me otherwise.

fasteddi

iTrader: (2)

No I agree with ya 100% on the R12, I think them outlawing R12 was dumb and there are alot of other chemicals that are far worst for the enviroment that are still out there and legal. R12 is the best there will ever be for Refs.

Reid Fleming

iTrader: (2)

This is the key to comfort in muggy Houston. We get dew points that stay in the mid 70's all summer long. Even approaching 80 from time to time. Something that's blowing 45-50F out the ducts will cool a car, but it won't really be comfortable because most of that cold air is going to dehumidifying the air instead of cooling the air. That's why once you cross into the 30's, a whole new world of comfort occurs. (Dehumidifying is HUGE at this level, hence the lake of water coming out of my evaporator) Getting into the low 30's, the air starts to feel stiff coming out the ducts.

I think you got those oils above mixed up.
HCFC = Mineral or AB
HFC = PAG or POE....R-134a is an HFC.

I'm running R-406a. It was developed back in the early 1990's. Runs in mineral oil. Returns the oil through the system very well. It's a combination of the below.

55% R-22
41% R-142b
4% R-600a

Boiling point is -28F. Better than R12 (-21F) or R134a (-15F).

The R-22 is what gives it the performance. (R-22 boils at -44F) Can't run straight R-22 though, as the pressures would blow up your system. The R-142b brings the temp/pressure back to R-12 levels, albeit slightly better than R-12. The R-600a helps with oil circulation.

I've been running this for 5 years now. The only thing out there that can give it a run for cooling would be the higher strength HC blends that Fast355 runs.

My car cycles off at 26 psi at 30°F duct temps. Evap runs about 10F colder than that.

Reid Fleming

iTrader: (2)

Freeze 12 is a genius at marketing.

1) They call it freeze.
2) They call it 12
3) People think Freeze 12 = colder version of R-12.

In actuality, Freeze 12 is 80% R-134a and 20% R-142b......R-142b is a warmer refrigerant than R-134a. Freeze 12 has absolutely nothing in common with R-12. They say you don't need to change the oil in it (leave the old mineral oil from R-12 days in there). This is barely truthful. Because yes, the R-142b runs in mineral, but R-134a does not. And the R-134a is 80% of the product after all.

Digging through their webpage, you'll find them saying that improved performance will come from changing to POE oil.

92RS4US

well I don't know about all that, but in '94 when Ca banned the use of R-12 in automotive applications the only solution was R-134a. I worked for a Saturn dealer at the time and I had to be certified to handle R-134a and be certified on using the equipment and retrofitting older vehicles. R-12 had been phased out and could not buy it through auto parts stores. So from '94 thru '07 living in Ca and retrofitting vehicles with R-134a I saw NO problems with the change over, really only complaints were it didn't cool off as fast. I did the retrofit on my own '92 saturn before I did the retrofit on my '87 RS with no issues. Now that I live in AZ it was never a thought of using R-12. You can still get R-12 for vehicles but its like $50/lb!!!! I get R-134a for free...its a no brainer.

fasteddi

iTrader: (2)

Sorry Im wrong and got them messed up

HCFC=mineral or AkyB
HFC=polyester oils/PAG
CFC=mineral

You ever get that POE oil on ya??? Man will that stuff suck the moisture out of ya, hands will be dry in a minuet! I guess thats why they sell it in metal cans and not plastic jugs.

Reid Fleming

iTrader: (2)

For awhile, there was an issue with even non opened plastic jugs of PAG having extremely high moisture rates just from sitting.

How much did the Saturn dealer charge to convert back then?

What kind of duct temps do you get in AZ with R-134a?