Next Project: AIR CONDITIONING (ES-12A)

[Dialcaliper]

ES-12a (Isobutane/Propane) or Propane can definitely perform better than R-12 in a system with properly sized evaporator and condenser - otherwise noone would bother using it.

Flammability is not all about flash points - anyone quoting only those is either misinformed, or not telling you the whole story. Flash point is only one piece of the puzzle (flash point is the lowest temperature at which the liquid puts off flammable vapors - nothing to do with what it takes to ignite those vapors). It also depends on the pressure - often quoted are the flash points at 0psi and 5psi, both of which are near vacuum.

More useful figures are autoignition temperature and flammability limits (in air). Autoignition is when a gas mixture will spontaneously ignite, in the absence of any spark or initiation (kind of like compression ignition in a diesel engine). Upper and lower flammability limits are the maximum "rich" and "lean" conditions at which a vapor can be ignited *explosively* (as opposed to just burning lazily)

These are from single sources - due to the very loose definitions of what each blend is, you'll find different ones everywhere.

R-134a (Tetrafluoroethane)
Autoignition: 1418 F
UFL: None
LFL: None (will burn but not ignite explosively)

ES-12a/HC-12a (Propane/Isobutane/Ethane Blend):
Autoignition: 1246 F
UFL: 9.0% (10:1)
LFL: 2.6% (37.5:1)

Also, propane/isobutane are sensitive to ignition by static electricity, which conveniently enough, is generated when it flows from a pressurized system into open air because it is a quite good electrical insulator. Fluorocarbons like R-134 are slightly conductive (due to the fluorine), and thus do not generate much static, nor are they very sensitive to igntion because of it. The stuff you often see marketed in cans as "antistatic dusters" or sometimes "air in a can" (although this is sometimes just nitrogen) for electronics is also tetrafluoroethane, or another fluorocarbon.

It's not to say that R-134 is perfectly safe, but in most situations you'll see in a car, it's pretty inert.

Instead of bantering about with designators like "ES-12a" or "HC-12", think of it this way. "I'm going to fill my potentially leaky air conditioning system with a mixture of propane from my grill, butane from my pocket lighter and a little bit of natural gas byproduct from my gas stove".

The thing that these all have in common is that they are all fuels. If you're cool with that, then more power to you. As far as hazard level goes, I'd put it at about the same level as trusting a DIY nitrous system installed by a previous owner of a car. Fire extinguisher recommended but not required. /ubbthreads/images/graemlins/uhh.gif

 

[turbowop]

Informative. Thanks. /ubbthreads/images/graemlins/grin.gif

 

[curtis]

Quoting DR1665:
came in a Coors box, so no paperwork, but it's got the Mitsubishi label on it "FK105V" or something like that.



Thats your problem. Damn mitsubishi engineers been up on top of the mountain with toybreaker killing brain cells /ubbthreads/images/graemlins/rofl.gif

 

[DR1665]

Quoting Dialcaliper:

R-134a (Tetrafluoroethane)
Autoignition: 1418 F
UFL: None
LFL: None (will burn but not ignite explosively)

ES-12a/HC-12a (Propane/Isobutane/Ethane Blend):
Autoignition: 1246 F
UFL: 9.0% (10:1)
LFL: 2.6% (37.5:1)

Instead of bantering about with designators like "ES-12a" or "HC-12", think of it this way. "I'm going to fill my potentially leaky air conditioning system with a mixture of propane from my grill, butane from my pocket lighter and a little bit of natural gas byproduct from my gas stove".

The thing that these all have in common is that they are all fuels. If you're cool with that, then more power to you. As far as hazard level goes, I'd put it at about the same level as trusting a DIY nitrous system installed by a previous owner of a car. Fire extinguisher recommended but not required. /ubbthreads/images/graemlins/uhh.gif



Not to be a dick, because I respect and appreciate your sharing details such as you have, but if I might offer the following (with a sh*t-eating grin on my face)...

Shell Rotella-T "Synthetic" 5W-40 motor oil
Flash Point: 399 F
Upper/Lower Flammability Limits: 1% - 10%
Autoignition Temperature: 608 F

So, I like to think of it this way. If I can make a point of ensuring that my most likely leaky Mitsubishi 4G63 is filled with over a gallon of a petroleum product that flashes at less than 400* to such a level as to ensure the substance flows through the turbocharger, just inches away from cast iron known to get to 1200* or more, then I'm not going to be too worried about the less than 12 ounces of less flammable, pine scented lighter fluid circulating through my freshly rebuilt with brand new o-rings from the Mitsubishi parts counter AC system. So long as the air inside the car blows at a temperature below, oh, 40* (which I've seen it do with this stuff).

That said, we are still on for this project over the weekend. Have refrigerant, oil, fittings, and hoses. Compressor is still slowly draining. All the lines are cleaned and ready for new o-rings. Found my missing GVR4 AC tensioner bracket (so I don't have to re-use the hacked DSM unit).

I'll be re-wiring my JDM headlights and re-installing the OEM pusher fan while I'm at it, as well as painting the core support on the car, which was replaced by the previous owner. Car is a near-Kensington Gray, but core support is sorta-Champagne. Plan is to start tearing down tomorrow after dark. I'll be posting pictures on Twitter while I work. If anyone wants to check it out, go to click and search for #gvr4

Cheers.

 

[Dialcaliper]

The only difference here is that the oil is contained in an armored, water cooled casing with plenty of thermal mass to keep it getting too hot. Likewise, the most dangerous liquid in the car, the fuel tank, is located in a fairly safe, low location in the car.

The A/C condenser happens to be mounted in one of the most vulnerable locations in the car, contained in a flimsy condenser core, outside of all of the crush zones. Now I know noone plans on being the one at fault in a collision, but risk exists.

As a side note, I certainly hope that R-134a is not toxic, because the asthma inhalers I occasionally need to use still use it as the aerosol propellant

From personal experience, I can tell you that an 8oz aerosol can (under modest pressure, less than 100 psi) of liquid butane from the convenience store on the corner can fracture cinder blocks and make a 12 foot high fireball when detonated. Based on that piece of trivia, I personally would not put any "alkane" hydrocarbon in my A/C system.

If you're that convinced to use it, then I guess noone here is going to convince you otherwise, and I wholeheartedly wish you good luck.

 

[DR1665]

Appreciate the concern and intelligent insight, sir. /ubbthreads/images/graemlins/applause.gif

Spent about four hours in the garage tonight getting started. I thought the gods would be smiling upon me, what with the wind picking up and a thunderstorm rolling through (made for cooler weather), but the rain passed through quickly and left things muggy as hell. Ugh.

Foreword: BOTH my Galants have been in front end collisions. I was behind the wheel of 195 for that one and 464 came with the repairs already done. Neither is pristine, but I like 'em both, and I'm known to be in favor of repairing rather than parting these things out, so with that in mind, here come some pictures before I call it a night.

Here's the bulk of my goodies. Three cans of lighter fluid /ubbthreads/images/graemlins/uhh.gif, a bottle of ester oil (OEM compressors ship with Sunisio 5GS oil, a napthanic mineral oil - got it at NAPA since Autozone only carries the PAG synthetic stuff for R134 systems), fittings, hoses, new o-rings from the Mitsu dealer, and the compressor, draining in a pan. Not shown are the condenser core (I need to clean it tonight before bed) and compressor bracket (still installed in 195).


This is what I started with tonight. You can't really tell from the fabulous blackberry cam pics, but the grille is actually Belize Green. Ironically, the grille in 195 (which was Nile Black and is now flat black), was Summit White. Guess you could say I have love for all the colors. (But black is the fastest, right?) /ubbthreads/images/graemlins/rofl.gif


Detail shot of how the new core support was installed on this Galant. Notice the lack of paint on the welds, resulting in rust. I took a Dremel with a flap wheel sander bit to all the rust before spraying it all down with brake cleaner to degrease and clean it prior to paint.


It doesn't matter how clean I might get the engine bay, when the hood's up and you see the core support is a different color than the rest of the car, it throws up red flags. You guys might appreciate that this is what it takes to save a special car, but other people will see it as a hack job on a rice rocket buzz bomb. The champagne support has bugged me since day one.


That said, if I'm gonna pull all the front end bits off to install a condenser core (and rewire my headlights), might as well do something about it, right? Here's a tip: Never, ever throw away your old bed sheets. Especially not the fitted ones. They are extremely useful when painting on the car, as well as packing or whatever. Just throwing it out there.


I used Duplicolor Truck, Van and SUV touch up paint in the spray can. Code is T299 "Dark Shadow Grey." It doesn't quite match the original Kensington on the roof (the only place it's left), but it matches the darker gray in the engine bay pretty good and looks a million times better than it did.


And here's the results. I'm happy with it. Very happy, actually. I can finally feel good about popping the hood and showing it off.


One more bit before I call it a night, check out the orange paint on my turn signals. Isn't that odd? They still have the amber lenses in them, so I don't know when or why this was done. Go figure.


Not necessarily AC-related, but it's where I'm starting. Tomorrow I pull the compressor bracket off 195 and start installing AC bits on 464...

 

[DR1665]

An update! 464/1000 now has AC and it blows COLD. 55* in 114* ambient air temps, to be exact. I ended up going with the usual R134A charge because the guys at the shop that leak tested the system treated me very well. I'm going to post up more pictures here in a couple days, but I just got home and have company flying in tonight, so I'm tied up. Just wanted to share! This is awesome! Woo-HOOOO!

 

[dsmless]

Yeah I went the r134a route too, and it has ben blowing out 57 in 89 degree wheather with lots of humidity in the air, the only problem is that I have to use a manual switch to engage the compresor clutch, but it works great, have to turn it off on trips or it will give me shivers, see how it will hold up in the tucson az 110 plus wheather i will be in in about 2 weeks, so any one wanna do a meet in az

 

[DR1665]

Don't know any GVR4 peeps in Tucson, boss, but if you're up in Phoenix on the second Thursday of the month, a bunch of us meet up at In-N-Out Burger in Chandler (far south side of Phoenix) every month. Should be a decent turn out. I should be there this time around.

 

[GVR-4]

I didn't read all of this thread, but I was thinking there has to be some merit in using the most common refrigerant in new cars: R-134A.

 

[Dialcaliper]

R134a was only chosen as the industry standard because it
a) is relatively safe
b) is a pure chemical, not a blend, so it is easily recycled (blend refrigerants currently cannot be recycled from automotive a/c systems)
c) is more environmentally friendly than R12 (although Europe is apparently outlawing R134 soon in favor of even friendlier, less effective refrigerants like high pressure carbon dioxide or R152, both of which are incompatible with current systems)

there are plenty of more effective refrigerants, but they all are either blends or have other issues such as safety

One other safety point that bears mentioning is that when you get it really hot, r134 has a bad habit of decaying into phosgene, a gas widely used in industry, but also popularized as one of the chemical gas weapons used in WW1. In short, refrigerants all seem to have hazardous tendencies. It actually seems as though R12 is one of the safest

 

[dsmless]

In and out sounds very good right abut know, so thursdays it is will let you guys know of the situation, would be nice to meet some people in phx, like i did in virginia, very nice folks, see you guys soon