junk4u

iTrader: (1)

Hi Torlog, that snip came from a test that was documented at the SAE Alternative Refrigerant Systems Symposium.

I did not readjust the expansion valve at all, the expansion valve is not adjustable in my truck. However that does not mean you can't retrofit it if you knew which one to do with it.

The Expansion valve on my truck is the same OEM one for it 88515-16031-83.
Again nothing was changed or modified on my truck A/C unit to make this work. It is all pretty much stock settings with the same evaporator, expansion valve, pressure switch, condenser and compressor. Just make sure to change any o-rings that you have opened up and lubricate the o-rings before closing up a dry o-ring can mean a crushed torn up o-ring. Don't forget to change the accumulator aka drier, if you don't you will regret it later.

Still cooling very cold vent temps are still below 35 degrees.

To make it blow better, I have found out that the foam seals around the duct pipe connection need redoing to seal the air leaks. Putting that on my list of things to do.

Torlog

Thanks for the info, Junk. I am going to keep tabs on this thread, as I may try this when I rebuild my engine and have everything out of the way. I don't like R134a, but I like that R152a is closer to working the way R12 did. Thanks again.

junk4u

iTrader: (1)

No problem Torlog, if you want to check out my build which is were all the AC work start from here a link to the actual start of the AC work.

https://www.yotatech.com/forums/f199...l#post52110717

Since I own an 1986 4Runner originally I remember a few things that aren't on these trucks today. One of them being the foam insulation between the radiator and the condenser. Check it out, I think it helps.

junk4u

iTrader: (1)

I've been driving around a bit and have noticed that the temperature in the full sun around 89-90 degrees the vent temperatures were 40-42 degrees that's up 5 to 10 degrees and then later in the afternoon I get vent temperature around 30-35 degrees. Even so, the temperature was comfortable, but once your sitting in the car cooling and the temperature rises just a hair it always feels hotter.

I'm going to have to check the pressures hi and low to make sure its working properly. Could be over charged which may cause it to return heat back through. Don't think it's undercharged as it took almost 16-17oz. and I originally figured it would only need max 15oz. I will know more once I check the high and low side to see where my pressures are, maybe it could be a bad expansion valve.

WD_40

Man, this is cool stuff (no pun intended or desired). I've been needing to fix up the AC in my '85 'Runner and I really don't like the idea of 134a. Thanks for taking the time to document your work. I think I'll end up going this route too.

gennro

I'm going to give this a shot, my AC doesn't work worth a crap in my 84 running R134a.

gennro

Finished up my conversion and was getting vent temps down to 36F at 1800rpm sitting still and at idle of 41F. Outside temp was 77F. Well worth doing, a lot less load on the engine also!

junk4u

iTrader: (1)

That's fantastic, I'm still running test. I'm having problems with the high side valve the schrader valve seems to have a problem and I can't get a reading from it, but judging by the low side it maybe very well that my expansion valve isn't working correctly. I've been logging my pressures (low side only) and keeping track of the vent temps during different times of the day for ambient temperatures affect the the pressures with the compressor. The data is invalid because I don't have any reading from the high side. I am trying evacuate the system and replace the shrader valves and the expansion valve. Hopefully once that changes is made I can get better readings here. As I want to let everyone know that has a stock AC system in their First Gen 4runner 22re what specs it will cool at the best.

Yeah, it is less a load on the engine and it is much quieter than it would have been with R134a. Sometimes it's harder to hear that clicking of the clutch going on and off.


Can you post your Pressures if you have them so that I can log them as well, so far we have 36F at 1800RPM and 41F at idle assume 750-800RPM with ambient temps at 77F

NARFALICIOUS

Hopefully you update this thread next year. I'm sure it works fine now. Just gotta wonder what design issues will come up long term.

junk4u

iTrader: (1)

I'm still running test on it. My a/c is basically stock with the exception of the drier, so nothing is retrofitted to make this work. I am looking for peak performance using the R152a and hope to post the data so everyone can use it with stock equipment. Here South Florida it probably the best place to test it out not only is it hot, but the humidity is high, means the evaporators work OT to remove that moisture out of the truck.

Also, right now it's got to be the most economical choice and it's on the EPA's choices to replace R134a in 2017.

I hope to start posting data once I get better readings from my gauges.

aztoyman

Great write up Junk. Thanks for sharing all your test data. I'm sure there will be plenty of conversions after you get this sorted out.

My R143A conversion works great but I like the idea of an alternative refrigerant.

I also hope you do a long term follow up on this.

j2the-e

Nice write up, I've never heard of it before. I would like to point something out though. Your vent temp readings using an infrared thermometer is not very accurate. You should use a real vent thermometer. If your A/C is in fact blowing below 32 degrees, it would only last a short time before the evaporator box freezes and the air stops blowing. Especially in tropical humidity like FL. And I'm not sure where you buy your R134a but I just paid $90 for a 30 lb can. That's less per pound than your 12 ozs of dustoff.
But if it works better than R134a in an R12 system, I'd be willing to give it a try. I've never been happy with the performance of R134 conversions

junk4u

iTrader: (1)

Hi j2the-e, thanks for the input, I can use all the input here as we go along.

Starting with the vent temps, you are so correct that using a infrared thermometer is not accurate and can vary. I have checked with a pocket thermometer and temps were with in reason 35 degrees. You bring up a very good point, but our trucks AC will not freeze up as they were equipped with a thermistor which senses the temperatures working with the amplifier cycling on and off the compressor, but then again if the thermistor is broken the chances of it freezing up are very high.

You bring an interesting point on the cost of R134a, first your price is very good for a 30lb canister of refrigerant, but it is highly unlikely that many of us would want to buy that much R134a to have around. EPA is looking to restrict the sales of R134a like they did with R22 and the 608 certification required. If my current tests shows that it works very good, I am looking to purchase from another source other than the duster blower cans. For instance, Airgas does handle this products, but I believe it is a 6lb canister and the fittings to connect to it would be a problem right now.

junk4u

iTrader: (1)

Hey Aztoyman, thanks for chiming in. The data is still processing and some changes have been made. Didn't like my readings on the gauges, so I ended up replacing out the expansion valve (erratic readings). It is cooling great, just waiting for a clear, hot sunny day to take more readings other than 86 degrees with over cast.

As far as the R143a, did you have to retrofit anything? My understanding is that you can use R143a in a car and it has been test and document in the library by the EPA, but test done indicated it should be applied in a cycle with internal heat exchange to have the best performance.

gennro

AC still working great and blows ICE COLD!

junk4u

iTrader: (1)

That's great gennro, keep us posted over time.

I'm finding that on sunny days, the temp in the truck reads close to 100 degrees. Cooling it down inside the truck took about 5 to 10 minutes even though the vent temps were 44-47 degrees outside was 88 and sunny, but it stayed cool after that. Some day i got to get under the dash and square away those air leaks before the vents. I can feel the air blowing under the dash.

junk4u

iTrader: (1)

R-12 (EPA restricted sales to 608 and 609 certification)
Dichlorodifluoromethane commonly known as R-12 Freon, it is a colorless gas, and typically sold under the name Freon R-12. It is chlorofluorocarbon halo-methane commonly known as CFC it was used as a refrigerant and aerosol spray propellant. Complying with the Montreal Protocol, it was phased out in the United States since 1994 due to concerns about damages to the ozone layer. R-12 has an Ozone Depleting Potential (ODP) of 1.0 and a Global Warming Potential (GWP) of 2400

PROS: Works well with older car systems as they were designed for this refrigerant.
CONS: Expensive, hard to get, requires EPA Certification for handling, Ozone depleting and high Global Warming Potentials.


R-134a (Does not fall under the restriction of sale guidelines by EPA)
1,1,1,2-Tetrafluoroethane commonly known as R-134a or HFC-134a, It is also a colorless gas and typically sold under the name R-134a. In 1994 R-12 was phased out and R-134a became its substitute. R-134a is a haloalkane with thermodynamic properties similar to R-12. The phase out of R-134a began in 2011 in Europe with a total ban due by 2017. In the United States, there is a 2017 target date to replace the R134a Freon with a newer refrigerant. At this time R-134a has not been banned, but will be federally taxed so its price is forced up. The tax is intended to further discourage people from attempting to frivolously use R-134a such refilling a system with a leak and force them to repair the leak. R-134a has an Ozone Depleting Potential (ODP) of 0.0 and a Global Warming Potential (GWP) of 1400

PROS: Available in stores works well with newer cars that they were designed for.
CONS: Getting expensive, not as efficient on older cars, has a high Global Warming Potentia


R-1234yf (EPA choice replacement for R-134a, but is not a drop in).
2,3,3,3-Tetrafluoropropene commonly known as R-1234yf or HFO-1234yf a carbon dioxide, it is also a colorless gas and is a proposed replacements for R-134a in the automotive air conditioners. It was reported that tests by a European auto maker showed that the substance ignited into a ball of fire when researchers sprayed it and A/C compressor oil onto a car's hot engine. The product is classified slightly flammable by ASHRAE; several years of testing by SAE proved that the product could not be ignited under normal conditions experienced by a vehicle. R-1234yf has an Ozone Depleting Potential (ODP) of 0.0 and a Global Warming Potential (GWP) of 4

PROS: Looked at as the number one choice for replacement of R-134a
CONS: Slightly flammable, mostly unknown right now.


R-744 (Another choice by EPA as a replacement for R-134a)
Carbon Dioxide commonly known as R-744, it is also a colorless gas and is also consider a proposed replacement for R134a in automotive air conditioners. It is non-flammable, non-ozone depleting (ODP), has a global warming potential (GWP) of 1, but is toxic and potentially lethal in concentrations above 5% by volume. R-744 can be used as a refrigerant in climate control systems for automobiles, home air conditioning, hot water pumps, commercial refrigeration, and vending machines.

PROS: Another choice for replacing R-134a, zero ODP and one of the lowest GWP of 1
CONS: None at this time.


R-152a (Considered as a choice by EPA for automotive cooling)
1,1-Difluoroethane known as R-152a or HFC-152a. Most people don’t know that it is a common office product that we use almost every day and is commonly found under aerosol propellant. EPA has this as an acceptable replacement for R-134a. It is slightly flammable, non-ozone depleting (ODP), has a global warming potential (GWP) of 120.

PROS: Available at most office supply store as a duster, relatively inexpensive and has a rating for the ODP of zero and a GWP below the coming newer standard of 150.
CONS: Slight flammable, limited testing was done by hobbyist looking for an alternative to R-134a in older cars. Most tests have been slightly better than R-134a and with the coming change this alternative which is currently available to retail customers it’s not a bad choice.

Anyone looking to change to any of the refrigerant above from what they have currently, should know that a good cleaning of the system should be done. I first replacement my drier after cleaning and tried R-152a with some varying results that could have been avoided if I had listen to myself in the first place to replace the expansion valve. I finally replaced the expansion valve and the results were much better than prior readings. I will post my result in detail as soon as I have completed them.

It also should be known that it is illegal to intentionally vent all CFC, HCFC, and HFC refrigerants including, but not limited to, R-12, R-22, R-134a, R-404A, and R-410A during any service, maintenance, repair or disposal of an appliance. So even though some of the substitutes may be ozone or Global warming safe, it is illegal to vent once it has been charged into you’re A/C units.

EPA had a test done back in the early 90's looking for the best replacement for R-12 I have underlines in red in the notes indicating the findings.

junk4u

iTrader: (1)

Okay, it’s been a while since my last posting on the Freon testing for R-152a. Ran into a couple of issue since like had to work on the engine again since one of my bearing cap nuts backed out and caused a bad knock and engine failure. Got that all fixed up a month ago. I never touched the AC when working on the truck as it sat for about 1 month till I got it back home and fixed it up again. Once I cranked it up and got everything running I drove it around and turned on the AC. Took about 2 or 3 minutes before it got cold. And cold I mean really good cooling. I was amazed at how cold it was even with the outside temps at 89-90 degrees outside. I thought that since it sat for some time I would surely find a leak or change in something, but so far so good.


There is one thing that I did do temporarily as it was part of my postings which was the space between the condenser and the radiator. I originally put a small towel between that gap, but when I was working on the fixing the engine it dawned on me that the towel was being pulled or sucked down. At that point I grabbed another towel to thicken it in hopes that it wouldn’t be sucked down with the vacuum creating a stronger draw of air through the condenser. Well it worked out and air seems to be flowing better through the condenser cooling it down


So my readings for now on my AC are as follows:


High side pressure: 190-195
Low Side Pressure: 25 – 28
My idle speed roughly: 1500rpm
Outside temps: 85-90 degrees
Vent temps: 42 -48 degrees


Cost to charge the AC:


Ester Oil: $10.00 it’s an 8oz bottle so you will have a bunch left over.
R-152a: a little over 2 cans $7.98 (Price went up I check on it the other day and 2 cans are now $8.98)
New Dryer: $16.00
New Seals (o-rings): $7.00
The Can Tap: $16.99
The Compressor : I already had this, so that was a freebie, you can get a loaner from the parts store.
Gauges: I had this also and you can get one as loaner as well.


Cost for me was: $48.00 complete.


Next time I do this the cost should roughly be about $10.00 bucks depending on how much R-152a is a the time as everything else I already have.

aztoyman

Hey Junk, Thanks for the updates.


Sorry I didn't answer the last question you asked me about converting from R12 to 134A. I just noticed it.


I just swapped in a different expansion valve and dryer. I was told the expansion valve was different/designed for 134A and the dryer was compatible with 134A and Ester or PAG oil. I chose Ester oil.


Was working great in Arizona heat. I recently did a 3.4 swap and used the 3.4 compressor with my existing system and it still works great.


I'm still interested in your conversion and appreciate your thorough documentation and updates.

paintthetown

iTrader: (1)

When I purchase the items u listed, like the dryer and compressor etc. Should I buy for a R12 system? Or 134A? I'm running R12 still in my 1987 4Runner still works. Just want to plan for the future. Thanks