I've often wondered why we don't go back to ammonia as a refridgerant. It couldn't be much more dangerous than some of the substances that have already been mentioned. It seemed to work very well in ice plants and such.

I think that the EPA's record on refridgerants has been poor or worse anyway. I believe that 134 will be gone before long. It required a lot to do a successful conversion and didn't work all that well anyway.

David Duffield

Andy:

I realize that everyone has added their two cents worth. But if you read the thread, you will see that the original question evolved into many. Ed simply had many questions and not just one. We are all here to help one another, even if it is not as direct as some would like.

Peace brother.

Kobalt, I have that vacuum problem myself. I need a vacuum. I private messaged some propane pelicanhead here in Phoenix, but I got nothing in return. If only we could find some propane pelicanites in our neck of the woods with vacuum pumps.

I already drilled the propane tip like Steve said. Or maybe I kind of did like Steve said. Steve, give us a picture man. Jurgen, what did you use to put it in?

Ed, I'm sure you did alright. I just mic'd the hole I drilled at around 2 mm, although I don't think the size here matters too much. I think there's some kind of check valve at the tip, so drill it all the way through, and empty out the the metal shavings. On the bottle side of the torch adapter, you can screw off the port with an 8 mm socket. Then you can drill the check valve out of that. Don't make this hole too big, because it must be small enough to push the pintle valve on the propane bottle. Not sure if this is necessary though. It might work leaving this alone.

The threads on the end of the torch tip do not match those on a standard AC hose. Find the correct die, and rethread the brass threads to match your AC hose.

Making custom threads to subvert gas handling system safety features is a slippery slope. I hope you guys have the sense or the knowledge not to do this with acetylene or oxygen systems. Mess with these and they might not find enough of you to fill a shoebox. :eek: If you consult your local fire marshal you will likely find all these kludges are illegal and will void any insurance coverage of damage you may cause. I suggest you request more guardian angels!

Now to correct some errors stated above:
R134a refrigerant performance is only about 8% less than R-12 not 50%. Due to slightly lower and higher pressures in the cycle, R134a requires modestly stronger and more leak tight system components. Optimum performance with R-134a also means valves and switches should be recalibrated for the higher pressures. The higher pressures while the vehicle is idling also require either a bigger condenser or increased air flow across the condenser. A properly designed R-134a vehicle A/C system can freeze your ass off if required.

Cheers and many happy vapor compression cycles to you. Jim

Steve and Turbo, do you guys just pour out of the fresh bottle of propane? I am asking this because on another forum somewhere, someone mentioned running the propane torch for a couple of minutes to burn off any moisture content if present in the bottle. Just wondering.

How's this, Ed. My brother and father did the mods (I was responsible for vacuum, charging, and making a huge mushroom cloud explosion).

Remove the tip of the torch. Solder on a 1/4"-1/8" reducer fitting and a 1/8" to male refrigeration flare. On our torch, there was no hole in the tip to drill out. It was wide open. On the end that attaches to the torch, remove the prong fitting, drill out the torch really big, but don't drill out the prong fitting too big. If you do, the prong will not press down the pintle on the propane bottle.

Please don't mind the Porsche porn PolyBronze bushings in the background. They were posing, so I had to take their picture. ;)

Any other pictures you need?
Jürgen

http://forums.pelicanparts.com/uploa...1086228067.jpg
http://forums.pelicanparts.com/uploa...1086228083.jpg

Ed, moisture in a system with propane doesn't create the acidic byproduct, so a little moisture won't hurt. I charged from 2 used bottles (used digital scale to measure charge), so moisture probably wasn't an issue.

Just be aware, like mentioned before, 100% propane will give you mighty high pressures. If your system isn't in good shape, you might uncover its weakest link. I plan to vent the propane and recharge with isobutane/propane mix to reduce pressures before it gets really hot and high side pressures skyrocket.
good luck,jurgen

If your system is perfectly sealed, sure you can. However, when you connect your gauges, you will be letting in some outside air, until the hose to manifold is pulled to vacuum. I don't think this is a BIG problem.

The ideal circumstance would have you renting a vacuum pump from a rental store (if possible), and pulling a vacuum yourself to be absolutely sure your seals and hoses are fine. In my limited experience with older A/C systems, taking a few extra steps can yield big improvements or at least give clues to the condition of your existing system.
jurgen

Look at all Porsche junk yards, a lot are from rear engine fires. I will be installing Duracool in my 88 this weekend. I pasted the below info from thier web site. I have seen a lot of info about this stuff lately. Rarely have I heard anything about using propane.

EDUCATIONAL INFORMATION
DURACOOL® Refrigerants Inc. are the leading hydrocarbon refrigerant on the market today and that's because it provides consistently superior cooling capabilities and boasts all the qualities of a product that is not only safe and highly efficient but it is also NON OZONE-DEPLETING and NON GLOBAL-WARMING. Here are the facts:

NON CORROSIVE - WON'T HARM AIR CONDITIONING COMPONENTS:

Guaranteed in writing!

Over 10 million vehicles converted to date.

System head pressures greatly reduced from R134a systems - similar to R12 systems

MUCH COOLER & MORE EFFICIENT! VERY SIMPLE INSTALL!

Cools extremely better than R134a - Cools marginally better than FREON

Up to 35% more efficient than R134a - Moderately more efficient than FREON

VERY SIMPLE INSTALL!

Simple economical conversions of high/low screw on fittings - NO RETROFIT REQUIRED!

Compatible with mineral & synthetic oils including Pag & Ester - NO OIL CHANGE REQURED!

No special equipment required for installation. Use your R12 or R134a equipment and tools

Requires only 40% of charge by weight of R134a and 35% of FREON R12

BETTER PERFORMANCE AND SAFETY!

Patented hydrocarbon friction fighter enhances performances and safety

Auto ignition of 1635°F is ACTUALLY a higher auto ignition than R134a which is 1328°F

Absolutely non-toxic - 100% natural organic product

Only if you are damned sure your system is leak tight, otherwise you could have the " treat" of seeing (perhaps the last thing you see) your compressor explode as that air and propane/isobutane mixture detonates within.:eek: Jim

Not that there's anything wrong with Duracool, but Duracool 12a is just a marketing name for hydrocarbon refrigerants. If you look at the MSDS, it consists of 30-60% propane, with the remaining balance as methane.

DURACOOL 12a® ACGIH(2002)
COMPONENTS % CAS LD50 LC50 TLV
v/v inhalation (ppm)

--------------------------------------------------------------------------------

(rat)
methylethylmethane 15-40 106-97-8 n.ap. 276,000 ppm 800
4 hr
(mouse)
2-methylpropane 30-60 75-28-5 n.ap. 52mg/kg
1hr simple asphyxiant
dimethylmethane 40-70 74-98-6 n.ap. n.av. simple asphyxiant
Non Hazardous Ingredients =<2 n.ap. n.ap. n.ap. n.ap.

pulling vacuum
 

For those looking for the poor mans vacuum pump, look no further than the cast off refrigerator down the street on garbage day.

9 time out of 10 the pump is fine, people just remodel and get rid of the old unit, or something non mechanical breaks.

Remove the old compressor for the unit, take along any start solenoids that also may be attached. I've got my "vac pump" mounted to an old milk crate with a handy dandy on off switch, but no need to get fancy. A dollar or two worth of brass compression fittings will typically provide some attachment point for a set of manifold gauges.

The suction side of the generic fridge compressor I use as a vacuum pump easily draws my system down to 25 inches of mercury. I can keep the "vac pump" running for an hour or two easily, so long as I keep it parked in the shade. Be aware that it does begin to run a little hot, as there is no longer any fluid circulating through the unit, but for the price I'm willing to eventually burn one out. As an aside, I have been running this one off and on for years without a hiccup. For really pulling a deep vacuum, I run two cast off refrig pumps in parallel. Did I mention I tend to collect all sorts of junk?

As there is no longer any oil circulating through the compressor , occasionally suck up the smallest amount of mineral oil now and then to refill the compressor crankcase. Easy does it, as you dont want to slug the compressor with a incompressible liquid. Then again, for the price you can afford to accidentally do some damage.


Cheap and especially ugly, but it works surprisingly well. Also incredibly handy for all sorts of odd jobs. If your really desperate, they also make incredible air pumps, capable of 300-400 psi pressure, so be sure your pressure vessel is appropriatly rated.

vin

You would need oxygen in the proper and sufficient proportions to create a large combustion like that. There wouldn't be enough oxygen, in any in the system to create any explosion.

The atmosphere is about 20% oxygen and will fill any leaking vacuum system up to atmospheric pressure with air that is 20% oxygen. Add the fuel (propane and isobutane) as you charge the A/C system and you could be headed for a heartache. Jim

Turbo, what pressures are you talking about. R134 kind of pressures?

Duracool is good stuff. By that I mean it is basically a propane isobutane mix. No problem with that. The main advantages are that it comes in the nice cans which you just connect to a regular r134 charging hose. Make sure you put on a 134 adapter on your low pressure nipple. But chances are you will find yourself doing this rig we are talking about here with the propane. That's because if you want to see some better numbers out of the vents, you gotta do a propane boost. It's all about the percentages. I guess in the case of a 911, after a full vacuum, you would use maybe 2 cans of duracool and then top off with pure propane. Or if it is filled already on just 2 cans, then maybe vent just a bit and put in the propane.

Higher--like 50-80 psi higher on the high side.

See http://www.delphi.com/pdf/techpapers/1999-01-0874.PDF

Perhaps you should read 90% of the other threads on Pelican, or any other public forum for that matter. There are many aspects and considerations to a question of this nature. Realize that if someone merely answered your question and this thread is read by others without a full spectrum of considerations then they may make an uninformed choice.
IMO, there's nothing wrong with considering safety and legality here.

Certainly there are safety issues to consider with R12A...but don't for a moment think that the issue of a nearly-empty 22 gallon gas tank is any less safe. Want to calaculate the explosive value of a nearly-empty 22 gal gas tank with gasoline vapors above the liquid level ???

Don't.......

---Wil

Sure. I wasn't trying to be a jerk, I just don't think Ed's question was "which refrigerant should I use, and is it flammable and/or legal" and he got several responses in that vein. Many other threads have covered those topics.

Thanks, jurgen.

Indeed. anyone in the denver area (or scottsdale for Ed) have a vacuum pump?

There should be an off the shelf refrigerant with equivalent performance to an 80/20 mix propane/isobutane. There's no reason I can think of that would prevent this product. I thought the enviro safe stuff was about 80/20 propane/isobutane, but I guess it's propane and cyclopentane, from the MSDS:

http://befreetech.com/esmsds.htm

In any case, I will probably be willing to pay a little more (and possibly sacrifice a little performance, but probably not) to have the convenience of R134a style charging rather than the propane rig. It is very interesting to see you guys doing custom rigs, though.

Anybody know anything about the cyclopentane?

TIA

If someone is trying to make this type of decision, they should at least be able to search the board. If they did, they would have found MANY other threads with opinions on various refrigerants.

Should each thread address every aspect of the system? Should a thread on rebuilding engines cover every possible tradeoff and choice of building every possible engine (2.0-3.8, cams, cylinder composition, bearings, valves, pistons, etc, etc. ad nauseum)? I don't think so. If someone is trying to solve a complex problem, they should do their homework.

anyway, please see my previous post for something on-topic regarding HC refrigerant compositions.

Nah Kobalt. I haven't found anything with the higher propane percentages. But I have heard that enviro-safe has something with a little more propane than usual. They say it's called the industrial blend. Don't know for sure though. Now I have to find someone locally with a vacuum pump.

Yeah, Envirosafe has an R22 replacement product as well, which is probably the industrial product you are referring to. I will probably use their R12 replacement and just see how it works.

I haven't searched for rentals on vacuum pumps, but it sounds like it may be tough. I guess I might try the old refrigerator technique posted (Thanks, vin!).

On a side note, I drove my '92 968 6-spd coupe today, which has a never touched R12 system. Damn that's a nice car, with ICE cold AC :D

It would be really great to see a performance comparison between the Enviro-Safe and/or Duracool and an 80/20 propane/isobutane mix. It might be possible to estimate with some educated guesses on proportions, plus the MSDS.

(edit: What I meant was it might be possible to estimate the relative performance with some educated guesses on the proportions of gases for which ranges are specified in the MSDS.)

Kobalt, I have a lot of news. First, I bought a full case of enviro-safe today. After all, it's cheap. I had plenty of fun playing with ac today. From the same guy I bought the enviro-safe from, I also bought a basic charging hose. This charging hose has a r134 can tap and an r12 end piece to connect to an r12 schrader valve on the compressor. He has all types of hoses and side tap combinations if required. I also got some stop leak. The enviro safe, like everything today, comes in an r134 type can, so that's why I needed a mixture of connectors. I got it from this place www.azaircare.com. The guy's name is Jack. I almost bought the standard enviro-safe, but then he told me about the industrial stuff. Standard ES12 is at best a 60/40 mix. But the industrial is 70/30. I bought the 70/30. It comes in taller cans. The guy is a previous 911 owner who is feeling the bug again. I forgot what I paid since I just gave him some cash and went on my way. Regardless, it was cheap by r12 standards.

Well, here is what I did since I got so much of the stuff anyway. First I took the car to a friend who took out almost all the freon in it. Just left a hair to keep some pressure in there. I just put in a full can at first, then let the compressor run. Just barely cool at the vents. Needed more. After that, I got out the benzomatic propane and added while watching the gauges. While the gauges were looking good, my wife inside the car holding 2k told me the temp at the vent was going just below 60. I quit there since the car was parked, the ambient temperature was around 105 farenheit, and the condenser is small. So I shut off the car, removed the gauges and took off down the road. Mind you, I am no ace when it comes to AC charging. I just know the safety basics, but not the nuances of gauge readings. I am sure that if some AC buff was messing around there, he could have lowered the vent temps another 10 degrees. Well here are the results after a quickie five minute ride on the freeway. At 105 ambient temperature, on the freeway it got down to around 45 and was still going down when I pulled off the freeway. Down the street it stayed at around 45. When parked, the highest I got was 60. Keep in mind the ambient temps. For me those are fine. My sister drove it said that's fine for her considering how f'n hot it was outside. Maybe I'll take it over to a buddy of mine's house this weekend so he can play with it. He is good with AC so I'll let him see if it needs more. Good stuff this propane.

Here is how I rigged the Benzomatic tip.
http://forums.pelicanparts.com/uploa...1086315270.jpg

First I got an r12 hose at an auto AC supply place. I cut one of the ends off. Then I got this adaptor thingy at Home Depot in the compressor accesory isle in the tool department. The tough part was getting the hose to go on that nipple. That's as far as I got. I'll try to push it in further tonight. The brass nipple I attached to the Benzomatic nozzle by using epoxy putty. It sealed real well. After all, I have used this stuff to seal boat hulls. Tough stuff. Just make sure not to block the holes on both ends with the Epoxy. Another alternative is to wrap some plumbers sealing tape around the Benzomatic tip and thread it into the nipple since there are threads on the inside. That should seal pretty good. I got no leaks on mine. Don't forget the drilling that Steve mentioned. It worked good. I'm happy. I think this is one great refrigerant. No pollution either.

I just put two cans of Dura Cool in my '87, works fine. It comes in a can exactly like the old R12 did, even has a little lube oil in it.

Nice, Ed, thanks for all the feedback! I'll be doing something pretty similar soon. I guess since you left a tiny bit of freon pressure, you didn't have to vac the system when you put your gauge set on.

Others: please do not tell us again about the legality issues of this. Ed and myself have both done our research. Thank you.

Sounds good guys. I can't wait to get my AC working again. I have a Cabriolet, but would enjoy having cold AC for those really hot days!

Others: please do not tell us again about the legality issues of this. Ed and myself have both done our research. Thank you.

Okay.


http://forums.pelicanparts.com/uploa...1086356594.jpg

I hope all the Bozos (epoxy bonded gas fittings!?) doing this know the difference between the discharge and suction sides of their systems; in R-12 systems the fittings are the same. An exploding refrigerant cannister is bad enough without adding a fireball to the shrapnel.

Ed, I have vacuum pump, recovery equipment, refrigerant scale, etc. and live in Gilbert area.

Point taken, Jim. I plan to use regular fittings with refrigerant in proper cans, rather than any drilling out of fittings etc. etc. Ed does seem to have done well, however. Really, I was just trying to prevent a tirade on mixing of refrigerants.

When I bought DuraCool I was advised that the fittings were unique to their product so I bought there stuff. I never even bothered to check against my equipment.

I just bought a set of guages to check my system and for adding some Duracool I just bought. I could just add a can but wanted to use the guages to see the current condition. I am unsure exactly how to use the guages...do I just hook up the higher side guage to the high pressure side and the lower guage to the other. What is the 3rd/middle threaded connector used for then?
Pics would be helpfu...
TIA

The third hose is ? (yellow) used to install the product of choice into the low side via the control valve at the top of the ? (blue) hose. ? (red) should be the high side. I hope this helps. Never,never,never install on the high side, it will explode the container. If I am wrong sorry. I hope this helps. Mark

I know someone that has run 8oz. of C5H8 in his car all last year and it worked good, now it needs the correct amount I think 12 oz shoulds work, but he is going to go back to r-12 or duracool now.

sometimes the FD gets notices from the fire marshals about industrial freons being used in cars and it being an explosive high risk..

So if I understand I just hook the high side hose to discharge side, the low pressure hose/guage up the the suction side and the yellow hose to the Duracool can. Can I just hook up the low and high guages to see what the pressure is now or does something have to be hooked up the the middle threaded opening to keep from venting the system?