malcontents

Hello all, I have a 1986 IROC Z28 that I would like to try running R-152a in. Currently, the A/C system is the R12 system and has a leak, resulting in the freon leaking out in about a week. I would like to tackle fixing the problem myself but would like to clear some things up beforehand. Firstly, what is needed to make my old R12 system ready for the R-152a? Is the system already compatible? I have access to some R12 but the supply is very limited and with my current leak I must be cautious about using it. Secondly, in regards to fixing the current leak, what are more common leak areas that I should check and can I rent a sniffer that can detect R12 from a store like Autozone?

sofakingdom

iTrader: (1)

Smart thing to do is not to "fix the leak"; but rather, tear the whole system down to its components, replace the ones that wear out or fail, and reassemble like new. "Fix the leak" in a 32-yr-old AC system is nothing but a game of whack-a-mole. Total waste of time and regrigerant.

New rubber lines are essential. Get "barrier hose" which is basically rubber-covered polyethylene tubing. Cut the factory crimped ferrules CAREFULLY off of the metal line sections with a wizz wheel and install the new hose in place of the old rotten stuff. Use 2 of the heavy-duty AC hose clamps at each hose end; NOT the little weenie things hanging on cards in the Cooling section at AZ.

Replace the compressor, accumulator/dryer, and every O-ring. Flush all metal parts - condenser, evaporator, and metal line sections - with some sort of NON-RESIDUE solvent such as lacquer thinner, MEK, acetone, etc.; NOT paint thinner, turpentine, brake cleaner, mineral spirits. Pour a bit into each part and blow through with compressed air, covering the far end with a clean white rag; repeat until the solvent comes out completely clear.

Never used 152A myself. I have no idea about "compatibility" or any of that. No clue what orifice tube would match it. No idea where to get it if I suddenly needed a can. No idea how much to put in or any of that. No idea what the best oil to use would be. No idea whether leak testers work with it.

I strongly advise against the use of "gimmick" refrigerant of ANY kind.

Use stuff you can actually buy when you need it and that's known to work (to the extent that it does) in our systems. Which is, 134A. With that, the correct oil, and a Frod red/orange orifice tube, which is a much better match for R-134A in a GM R-12 system than the white GM orifice tube for R-12 is in the same system when filled with 134A, the system will work nearly as well as it did with the FAR superior R-12.

QuickStyle

r134a is more efficient than 152a. i've experimented with several different refrigerants in the past, and if i remember correctly my tests showed higher head pressure with 152a to accomplish the same amount of cooling as r134a. there is no upside to using 152a over r134a.

Fast355

iTrader: (2)

WRONG!!

I have played with enough with various systems running R152a to discover that the head pressure drops approximately 40-50 psi and the cooling is noticeably better especially initial pull down and idle cooling. MY dual evaporator Express van was lucky to get 60*F at idle with R134a and was in the 300+ psi head pressure range. With R152a it dropped down to 260 psi and cooled 40*F at idle on a 105*F day. Going down the road I have seen 36*F vent temps. I had to swap the fixed cycling switch for an older adjustable switch and raise the compressor cut-out pressure about 5 psi to keep the evaporator from freezing. R152a is far superior to R134a in both a R12 and R134a system.

QuickStyle

Fast355, we've had conversations regarding HC refrigerants in the past via PM. i was not able to get the HC refrigerant to work properly, where you were able to get it to work great. i had given up on HC refrigerants and tested r152a, and it seemed to perform about that of r134a with higher head pressure, so i scratched the idea of using r152a. im not sure why it works so great for you, but from what i found it just makes no sense to use it.

here is a good read on a scientific study of r152a vs r134a, which the findings are exactly what i was getting when i tested it.

https://www.researchgate.net/publica..._passenger_car

4.0 CONCLUSION

Based on the numerical approach on the working fluid replacement of R134a with R152a in the automotive A/C system, the following conclusions are noted:

(a) The cooling capacity improvements only occur at the condensing temperature of 50oC. The highest cooling capacity improvement attained was 5.0%.

(b) The input power reductions occur in all the condensing temperatures, and the highest input power occurs at the condensing temperature of 40oC, that is up to 8.5%. The input power reduction indicates that the use of R152a leads to decrease in the fuel consumption for automotive A/C application.

(c) The increment of COP improvement is caused by the increase in condensing temperature rather than the increase in engine rotation. The highest COP improvement attained was 13.5%.

(d) The use of R152a as refrigerant leads to significant increase in the discharge temperature. This condition may shorten the life span of compressor

Drew

iTrader: (58)

I'd have an easier time accepting the results of their study if they were researching the merits and construction of a "Donkey-Bomb". I'm not too sure I trust the accreditation of Indonesia, Malaysia, and Nigeria. Especially when we are applying the refrigerants in question to thirty year old US automobiles.

Fast355

iTrader: (2)

Not sure why you are having issues with it or HC for that matter.

Same weather conditions, same system with no system changes dropped the vent temps 16°F in my Express van and about 10°F in both my Titan and my Infiniti M56 at IDLE.

On the Express van it worked so well I had to swap to an adjustable cycling switch and raise the cutout pressure to keep the evaporator from turning into a solid block of ice on a 100°F day.

Both the Nissan Titan and Infiniti M56 use a thermostatic probe in the evaporator that senses temperature.

The R152a seems to be able to shed heat more easily through the condensor and thus drop the head pressure from my experience which also causes a decrease in suction side pressure. On a 100°F day my Titan would run about 150 psi and 25 psi low side at idle with 40°F vent temps. High blower and recirculate. I tend to knock off recirculate after a few miles on everything I have tested it in because it gets the air so cold it hurts your knuckles.

82tarecaro

iTrader: (4)

What is the recommended orifice tube for use with R152A? I tried it in my 82 TA and it was marginal at best. This is after a complete overhaul of the system, including replacement of AC compressor, lines, evaporator and condenser.

sofakingdom

iTrader: (1)

This is why I recomend not bothering with that sort of thing.

Use what IS KNOWN TO WORK. Do it once, no experimentation, no having to go back and re-do anything, just in done out gone once.

Forget the "gimmick". Ignore the arguments and ethnic ... something. Use 134A and a red/orange Frod orifice tube.

Fast355

iTrader: (2)

I DID and even had R134a in factory R134a systems. Was never satisfied with the way it cooled. Evacuated the R134a, pulled a good long vacuum, recharged with R152a.

The 87 Firebird I charged with R152a recently has the OEM style 87 condenser, a 1992 style R4 compressor and lines to match the TBI style brackets on the TPI engine swap. Swapped over to a dual fan setup from a 4th gen car that has a full shroud.

It was 99*F when I charged the system. The Hotcam 350 idles at 850 rpm in Park with the A/C on. A/C temp at idle with the blower on high speed and the a/c set to recirculate dropped to 42*F. High side pressure was right at 200 psi, low side pressure 35 psi. Rev the engine up to 2,000 rpm, high side increased to 220-230 psi, low side drops to 26 psi, and the temps got down to 36*F before the compressor cycled off.

82tarecaro

iTrader: (4)

What orifice tube did you use?
Sofa - while I 100% agree with you, I figured there was no harm done giving it a shot. I actually have R12 and one of the reasons I tried the R152A first was to make sure that it would not leak into the next season. After 3 years it is still fully charged so I am 100% confident I will not lose the R12 charge when I switch over.

Fast355

iTrader: (2)

Factory size 0.072" White one that came with the a/c compressor kit.

My Express van has the Red .062" Ford.

Drew

iTrader: (58)

Oh come now, there's an Abdul and a Muhamad in the authors list. Are you going to tell me they shouldn't be on a watch list?

But really though, does any place really spell technology with a K and an I? That's the gimmick!

I kinda doubt anyone is jumping into running an alternative refrigerant on it's gimmick merits. Either you just want to try it and see, or you dislike 134a... Most people who have tried it have a reason for doing so.

Fast355

iTrader: (2)

^^^I have tried alternatives because I got tired of sweating on hot days, stuck in bumper to bumper traffic at or just above idle speed using R134a with its 60+*F idle vent temps even if factory R134a systems with electric fans.

BURD

I have the charging station and R-12. And a reclaim station, I'd stick To r-12 myself. I don't charge much to use my equip.

Fast355

iTrader: (2)

Just as a bit of proof as to how well R152a works and pulls down. My Black on Black M56S sitting in the sun in a parking lot in better than 100°F yesterday. At idle the a/c duct temps dropped from 140°F to 60°F in less than 3 minutes. R134 won't do that if you are driving down the road.

https://youtu.be/4z32nng8SkY

QuickStyle

what fan speed were you using for that test? recirculate? what was your humidity?

i will try this experiment tomorrow when i get out of work. should be about 99 degrees outside with less than 20% humidity when i test it.

Fast355

iTrader: (2)

Auto climate control, it ramps the fan up to high speed 10-15 seconds after startup and defaults to recirculate as the a/c head pressure crosses some threshold. You can be in outside air mode and it will automatically recirculate as needed.

Official weather at the local test station 2-3 miles away was 101°F and 36% humidity at the time that test was run.

I actually tweaked the a/c engine fan speed settings in the ECU when I tuned the car. From the factory under 20 mph the factory never commanded more than 55% fan speed. I tweaked them to run 100% at stop even when the car had R134a. I think Infiniti was trying to minimize fan noise but the a/c sucked at idle and the engine ran hot in traffic. I think this because at 20 mph the fans would run 100% speed at the same temps and pressures they would run 55% at idle.

QuickStyle

so i did the experiment similar to the one you did. it was sitting outside all day when i did the experiment it was 101 degrees with 25% humidity according to the weather. auto function on which puts fan speed on high within 15 seconds and auto recirculates, and the pull down temperature for my r134a is identical to your r152a, went from 150* down to 60* in under 3 minutes. i re-calibrated my thermometer before the test, but it has a sticking problem around 65 degrees, you can see in my video that is jumps from 65 down to 62 around the 2:40 mark.

things i can't account for a good apples to apples comparison are our humidity differences, different vehicles, i have a single dual speed fan with a full size intercooler in front of my condensor.

QuickStyle

went ahead and did the same experiment on my truck with r134a, 130 down to 60 in 3 minutes. outside temperature was 102* with 25% humidity. hvac in auto mode with automatic recirculate. i think the starting temperature is irrelevant and has to do with the type of vehicle and how close the thermometer is to the glass, i think what matters is the time it takes to actually get down to 60* because there is no other reason the starting vent temp in this vehicle is 20* less in the same weather, the inside of the cab felt just has hot as my car.

dual electric 2 speed fans with intercooler in front of condensor