iso-butane conversion from r-12 for 69 camaro

Good post, and good documentation, Steve.

Someone recently posted that Europe was looking at hypercritical CO2 as a refrigerant. Do you know what the status of this is? It should be about as safe as necessary from a toxicology standpoint, when used in the small volumes required by auto AC.

We were being forced to look at it as a liquid solvent in certain lab tests because the fluorocarbon solvents normally used were hard to get and unpopular.

Someone posted that it would be hard to find a leak with CO2, but this is a technicality that can be overcome.

You may remember that a lot of systems used to use anhydrous ammonia as a refrigerant. Not the most pleasant material in case of a release, but environmentally very acceptable.

Reply to
<HLS
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Isobutane is apparently assigned refrigerant number R600a and propane is R290, which is a common refrigerant in heatpumps in europe.

Thomas

Reply to
Thomas Tornblom

Try the automotive A/C site

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which has forums and FAQs.

A 60% propane and 40% iso-butane mixture by weight is supposedly a perfect but highly explosive drop-in replacement for R-12 (I've been told 100% propane behaves almost exactly like R-22). I've also heard you need to remove the moisture more thoroughly than with R-12.

If you use 60/40 propane/iso-butane, I'd be surprised if you needed a new expansion valve because it usually compensates quite a bit for different gases, and I kept my original one when I converted my VW from R-12 to R-134a years ago. However I also changed to a high-efficiency condenser because I lived in Arizona and it was only an extra $75. Does your 1969 Camaro even use an expansion valve? I thought GM has long used fixed orfice tubes or other types of valves that work on pressure rather than temperature. The best R-134a conversions include a new orfice tube, but in milder climates it's apparently enough to simply adjust the evaporator pressure switch for about a 4 PSU lower cutoff pressure.

Reply to
rantonrave

This, however, does not imply that either gas, alone or in combination, is appropriate or safe for use in motor vehicle a/c systems.

Reply to
Daniel J. Stern

If you really want to do this, track down a company that sells container of stuff ready to go into your system. They would also probably sell you the appropriate lubricant for your system. There should be a lable under the hood letting you know how much refrigerant your system needs. You then measure out the proper amount. You also want to put a label under the hood of the car so that anyone who subsequently services the AC system will know what type of refrigerant is in there.

----------- Alex

Reply to
Alex Rodriguez

Has it been shown to be unsafe?

R-134a does not work well in a system designed for R12.

-------------- Alex

Reply to
Alex Rodriguez

It can work perfectly in an R-12 system, if the retrofit is done correctly.

Reply to
Steve

As a matter of fact, during a demonstration of how safe it is;

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I'l save you the bother of doing the math, 343 grams equals 12.25 ounces (.7 lbs).

Not entirely true.

Then again, I can think of R-12 systems where R-12 did not work all that well (late 80s Ford E-vans come to mind)

Reply to
aarcuda69062

determines

considered

environmentally

Last I had heard the CO2 was meeting the same response as a fart in church. The systems have to run at such high pressures to be functional that any leakage makes them shut down. They are also having problems because it is no where near as effective as R-134A in a vehicle.

I have a couple AA units here, My large walk in freezer is AA. Nasty if it springs a leak but at least it is easy to find the leak......

Reply to
Steve W.

But there is a simple, obvious solution to all the safety concerns: Merely raise the atmospheric pressure in the vicinity of the vehicle from 14.7 PSU to 30 PSI by increasing only the nitrogen content. This will prevent combustion, and I've had it done for my house as well, as any parent who isn't criminally negligent would.

Reply to
Norm De Plume

Define correctly.

----------- Alex

Reply to
Alex Rodriguez

He's an idiot. That doesn't mean it is unsafe to use in an AC system. That's like pouring gasoline on the floor and lighting a match and saying that is why it is unsafe to use in your car as a fuel. What was the fool thinking when he came up with this experiment. Why didn't the other folks in the car stop him or get out. It is pretty obvious there was going to be an explosion.

------------ Alex

Reply to
Alex Rodriguez

True.

You're right, it means it's unsafe to use in an AC system that wasn't originally designed for it.

Not at all like pouring gasoline on a floor and lighting it. References to gasoline as a fuel and its safety are a non-sequitur since it's impossible to make an internal combustion engine run on anything that is not flammable.

He was thinking; I'll demonstrate how safe HC refrigerants are by simulating what would happen if a like amount were to leak from the evaporator and then be exposed to a spark. BTW, it was NOT an experiment, it was a demonstration to promote HC based refrigerants as "safe."

Because he was demonstrating how "safe" the HC based refrigerant is.

There hadn't been the previous times he'd conducted the demonstration. IOWs, the outcome this time wasn't what he expected.

Bottom line, those who crow that there aren't any documented cases now have nothing to crow about.

Reply to
aarcuda69062

I was asked to look over this thread from the guy who started it (inetquestion). I picked through some of the questions/quotes and in no particular order I have added my two cents.

(So, where did your two ME friends run off to then?)

One is right here.

(Is there a particular reason you don't want to stay with R12 / R134a)

R-12 is expensive and most people can't buy it. R-134a does not work well in many R-12 systems, for example: In my niece's Lumina R-134a works fine. In a Taurus it downright sucks. My guess is that the evaporator and condenser are undersized in the Taurus.

(Sure, in a system designed and intended to hold and transport flammable liquid and vapors. The A/C system is designed for use with NONflammable

refrigerant.)

I highly doubt that the system would be any different if designed for flammable refrigerants. Many of the connectors are quite similar to fuel lines that carry gasoline in a hot engine compartment at 60psi. As the AC system is evacuated there is basically no oxygen present, there can be no combustion in the system.

(I want to see if in fact it is a viable option, and can be done at a fraction of the cost of the other alternatives.) (HC refrigerants are selling for about $5.00 a can, R-134a is selling for $8.00 a can. No fraction there.)

The propane/isobutene mix *is* a HC refrigerant, why did you not include R-12 in your price list?

(Yes it is illegal.)

Three words "I don't care" R-134a is not a viable option for my

67 Mustang and R-12 is too hard to get. I also regularly break the law while driving, usually do about 75 in a 70 zone and some times I don't use my turn signals.

(But the gasoline is NOT circulating through a pressurized heat exchanger sitting 1 inch behind the front bumper of the car... Nor is it circulating through a heat exchanger INSIDE the passenger compartment.)

*And* if you get in an accident *and* rupture the condenser *and* it finds a suitable combustion source what do you think is going to happen to a few ounces of propane? Do you think it's going to make one of those huge fireballs that you would see when you used to watch Chips? Do you know that many windshield wiper fluids are flammable? Where do you think those reservoirs are located? I also can't think of an accident that would only rupture the evaporator and leave the rest of the AC system intact while maintaining a sealed passenger compartment, can you?

(Isobutane is apparently assigned refrigerant number R600a and propane is R290, which is a common refrigerant in heat pumps in Europe.)

Yup.

(A 60% propane and 40% iso-butane mixture by weight is supposedly a perfect but highly explosive drop-in replacement for R-12 (I've been told 100% propane behaves almost exactly like R-22). I've also heard you need to remove the moisture more thoroughly than with R-12.)

It's actually more like 80% propane and 20% isobutane.

(It (R-134a) can work perfectly in an R-12 system, if the retrofit is done correctly.)

Sure it can, if you replace every component with parts designed for R-134a. An R-12 AC system is also designed to use a refrigerant with specific vapor pressure characteristics, R-134a does not have these characteristics but the propane isobutane mix has almost the exact same characteristics as R-12. R-134a also tends to have significantly higher pressures in operation than R-12, stressing R-12 systems beyond their designed limits.

Here are a few things to think about:

The vast majority of refrigerant (liquid and gas) is located in the engine compartment that is extremely well ventilated. You have a small evaporator in the ductwork that only contains gaseous refrigerant and is well protected (by its physical location) in a crash.

If you develop a leak in the evaporator the refrigerant will probably exit through the condensation drain (propane is heavier than air) or you will smell the gas.

Many houses have natural gas and propane piped right into them, you read that right, piped right into the house. These pipes can and do leak and some houses do explode... but not many.

People carry around small amounts of potentially explosive hydrocarbon fuel in their pockets all the time; the scary thing is that the only thing between the fuel and the person is a cheap but colorful plastic case.

Do you realize that dozens if not hundreds of people are killed each year because tires blow out and drivers lose control of their vehicles? We actually drive around on rubber doughnuts filled with high-pressure air waiting for them to pop and send our vehicles into the ditch. How stupid is that?

"Inhalation of high concentrations of vapor is harmful and may cause heart irregularities, unconsciousness, or death" can anyone guess what *safe* refrigerant I got that quote from?

I know quite a bit about propane. While in school (Mechanical Engineering) a group of students and myself entered a competition to try and get aboard NASA's KC-135 "Vomit Comet". Our experiment needed to burn small amounts of propane. You will never in your life research and do more calculations regarding propane than when you are trying to convince NASA that it is safe to bring it aboard their airplane (we did fly and it was better than any roller coaster in the world).

I know I would rather breath propane over R-134a.

The point is that there is a certain risk in almost anything we do.

cell phone (remember all the brain cancer hype?). I understand the refrigeration cycle, and when I was researching using this *alterative refrigerant* I knew the air/fuel ratio, dispersion rates, ignition temperature and about a dozen other facts regarding propane and in *my opinion* the chance of having a refrigerant explosion in my car is so remote that it is trivial.

Mamushka

Reply to
Mamushka

Oh, you're here to convince us heathens, right? All under the premise of asking a question...

So maybe -you- can tell us why your friend didn't just consult you and the other ME student since you two did exhaustive research.

The first nights stay in ICU burn ward is likely to exceed $20K

Interesting... I have a customer who's 93 Lincoln Continental is retrofitted to R-134a and it cools just fine.

-My- guess is your experience with a Ford Taurus is more likely to be traced to an incorrect compressor clutch gap than it is to an undersized condenser. Forget the evaporator, it's no smaller than any other used in a mid sized vehicle.

Then you've never looked at the plumbing used on Propane or CNG fueled vehicles. The very nature of the contents demand that they be engineered and speced differently.

Whiskey Tango Foxtrot? Who said anything about combustion "in" the system?

Okay, R-12 can be had for about $9 a can. Demand is less, prices are dropping.

I believe the correct term to describe this is "sociopath."

Air conditioned cars are not an entitlement.

It doesn't need to, it only needs to start other things ablaze which otherwise normally wouldn't have started on fire.

Windshield washer fluid is not in a gaseous state, nor is it likely to be aerosolized like pressurized propane would be at

200+PSI.

Accident, maybe not. Normal wear and tear along with component corrosion? That I see on a daily basis. i.e., a rupture in an accident is NOT the only mode of failure.

So, you're claiming that your buddies 69 Camaro has a serpentine flow condenser?

The delta pressures would be very much along with what might be seen in a vehicle operated in Phoenix versus one operated in Minneapolis.

And all it takes is a small leak overnight in the evaporator and a small spark from the blower motor brushes and your whole point goes up in flames.

Probably? I thought you researched this? You can "probably" in one hand and shit in the other.

And I'll guarantee you that the pipes that bring natural gas into my house are a whole lot heavier gauge and made of steel compared to the light gauge aluminum piping used in an automobile AC system. Your comparison is ridiculous.

And these "small amounts" have what to do with an automobile system filled with 12+ ounces of iso-propane/iso-butane?

Okay, if -they- want to use propane in their cars, I'll go along with it.

You might, I don't.

I wonder...

Okay, so you flew in an airplane and went to school. How is that proof that you have even the smallest measurable amount of common sense?

I'll take a Scott Air-pack. Actually, you're not supposed to breathe either one, but choosing exposure to the one that has demonstrated flammability is just plain idiotic.

Oh boy, here comes the logical fallacy.

This guy used to think that also;

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Reply to
aarcuda69062

ammonia is also a very good refrigerant! and when you get a leak they just have to call EMS and they keep there vehs. nice and kewl.....there are MANY different refrigerants that work well but are not suitable for mobile use......kjun

Reply to
KjunRaven

(I was asked to look over this thread from the guy who started it) (Oh, you're here to convince us heathens, right? All under the premise of asking a question...)

I must say, you lost me right out of the gate, was my first statement (not a question) too confusing for you?.

(So maybe -you- can tell us why your friend didn't just consult you and the other ME student since you two did exhaustive research.)

He actually e-mailed me on a account that I don't check too often about the same time he posted here, wow, that was a tough mystery to crack.

(R-134a does not work well in many R-12 systems, for example: In my niece's Lumina R-134a works fine. In a Taurus it downright sucks) (Interesting... I have a customer who's 93 Lincoln Continental is retrofitted to R-134a and it cools just fine. -My- guess is your experience with a Ford Taurus is more likely to be traced to an incorrect compressor clutch gap than it is to an undersized condenser. Forget the evaporator, it's no smaller than any other used in a mid sized vehicle.)

First, a Continental is not a Taurus. Second, your "guess" shows your impressive ignorance. There are dozens of reasons why the air conditioning might not perform well. Why would you pull "clutch gap" out of your ass? Just to add a little empirical data, after doing the R-134r retrofit with poor results I dumped in my homebrew mix and got good cooling. I also worked at a Ford dealership while going through school and the AC guy refused to do retrofits on Taurus's because almost all of them came back. You can also check the archives at aircondition.com and see all of the love for Taurus retrofits.

(Air conditioned cars are not an entitlement.)

Where did I say that? Oh... I didn't.

(Do you know that many windshield wiper fluids are flammable? Where do you think those reservoirs are located?) (Windshield washer fluid is not in a gaseous state, nor is it likely to be aerosolized like pressurized propane would be at 200+PSI.)

So you believe that alcohol won't burn unless it's aerosolized? Also, since you used the big word "aerosolized" why don't you tell us how it makes things worse if the system ruptures.

(So, you're claiming that your buddies 69 Camaro has a serpentine flow condenser?)

See my answer to "entitlement" above.

(The delta pressures (R-12 vs. R134r in same system) would be very much along with what might be seen in a vehicle operated in Phoenix versus one operated in Minneapolis.)

That's correct. But I doubt that guy in Phoenix wants to drive North every time it gets hot.

(If you develop a leak in the evaporator the refrigerant will probably exit through the condensation drain (propane is heavier than air) or you will smell the gas.) (Probably? I thought you researched this? You can "probably" in one hand and shit in the other.)

This might shock you, not all cars are built the same. Most cars that I have seen have an open condensation drain and leaked gas *will* drain out. Some cars have a pinched hose acting as a check valve that *might* seal too tight for the gas to escape.

(Many houses have natural gas and propane piped right into them, you read that right, piped right into the house. These pipes can and do leak and some houses do explode... but not many. ) (And I'll guarantee you that the pipes that bring natural gas into my house are a whole lot heavier gauge and made of steel compared to the light gauge aluminum piping used in an automobile AC system. Your comparison is ridiculous.)

Are you remotely serious here? You're just screwing with me right? OK, I'll type slow here so you can follow: Think, why run pipes into the house? That's right, to connect to water heaters, ovens, furnaces, dryers and fireplaces. You can have failures of solenoids, thermoelectric devices (those are designed to shut off the gas if the pilot light goes out) or other components. In my last house I came home from work to a garage filled with natural gas, a 15 year old ball valve had a cracked body and started to leak.

(We actually drive around on rubber doughnuts filled with high-pressure air waiting for them to pop and send our vehicles into the ditch. How stupid is that?) (You might, I don't.)

I'll bite, you don't drive?

(I know I would rather breath propane over R-134a.) (I'll take a Scott Air-pack. Actually, you're not supposed to breathe either one, but choosing exposure to the one that has demonstrated flammability is just plain idiotic.)

Read the MSDS on propane, the only inhalation hazard is that if your standing in a hole it will displace the air. So your afraid of a little propane but you'll freely strap a cylinder pressurized to 2200 psi to your back ;)

(Oh boy, here comes the logical fallacy.)

OK, I must be slow, please explain "the logical fallacy" to me.

Bravo Tango Whisky: I need to thank you for making the great point about Thalidomide in your previous post, it reminded to pick up my prescription for Vioxx :)

Mamushka

Reply to
Mamushka

Not referring to your first statement, I was referring to your 'friend' and his original post. (try to keep up) As for confused... you seem to be in as much as whatever news client you're using totally sucks in regard to quoting convention. (your posts look like shit and are hardly readable)

You know, any time someone states "I have two friends who researched this in college and are experts" and then comes to a forum such as this to ask for approval, I gotta wonder exactly how much bull shit makes up the total content of his post.

Actually, it is. The part numbers for the condenser, evaporator, compressor, accumulator, low pressure switch and high pressure switch are the exact same.

No, my guess is based on the years I worked in a Ford dealership doing 90% of the AC work and the known common problems with their AC systems.

Because certain Ford vehicles are extremely sensitive to compressor clutch gap, those being Taurus, Sable, Continental.

Sorry, that's not "empirical," that's anecdotal.

Had to be in the wash rack since you aren't aware that the Continental is built on the Taurus chassis.

The guy I replaced at the Ford dealership doing AC work also had a lot of comebacks, seems he was unaware of proper service procedures. Maybe that's what you experienced.

You inferred it.

No, I believe that "windshield washer fluid" won't burn unless it's aerosolized. You should refrain from changing words and definitions in order to try to make a valid point, lest you look like a desperate doofus. Ooops, too late.

Oh, I dunno... maybe you want to contemplate something like the surface area exposed to atmosphere.

You inferred that his components would be sub-standard, I was just trying to determine which one you thought it was considering that a 69 Camaro would have come with a fairly robust assemblage of AC hardware.

He wouldn't need to. He'd only need to stop worrying since the system is designed to handle the extra load.

Yes, some cars have this and some cars have that. Your "probably" statement stands as worthless now as it did a few days ago.

Well, since I used to work for a natural gas utility and was in charge of maintenance on the four CNG compressors and cascade that supplied our fleet, yes.

What else does someone do to someone else who's as clueless as you?

Sounds to me like you practice sloppy maintenance on your NG fueled appliances. All the more reason to not put a similar gas in your vehicles air conditioning system.

Wrong. I don't drive on shit tires. Haven't had one of your supposed happens every day blow outs in over 25 years.

Okay, so discharge 13 ounces of propane into a closed car and come back and let us know if you suffocated. If you do this at night and you're having trouble seeing if you've suffocated yet, flick your Bic for a little extra light.

Certainly. That tank is designed for its intended purpose and is regularly inspected to be certain that it is suitable for what it's being used for. Other than stupid mistakes based upon not following procedure, do you know of anyone who's been blow up by a SCUBA tank that has failed? (hint; the end of the movie "Jaws" couldn't happen as portrayed)

Ever hear of "Google?" Maybe you should look it up in its context of usenet discussions. (hell, you might find your picture there)

A mimmic, how cute...

heh-heh... Off the market, just like HC blends for mobile air conditioning. Thanks for making my point.

Maybe you should pick up some Ginko Biloba instead, I've heard it improves brain function.

Again, for your viewing pleasure;

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I wonder if he said "hey y'all, watch this" before he blew the car up?

Reply to
aarcuda69062

Watch the video!

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Ted

Reply to
Ted Mittelstaedt

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