Info for R12 users - Page 2

ChrisM911SC · 07-20-2005, 10:08 PM

Ryan, are you running any type of rear tail or an 11 blade fan? This should pull enough air across the coil to dissipate enough heat to keep you cool. When I first acquired my car, I was tempted to change the turbo tail to a carrera and was quickly persuaded not to by several locals here in AZ. The increased airflow is definitely a plus with our heat.

bigchillcar · bigchillcar's Garage

chris,
i've got the 11-blade fan, but may upgrade the crank pulley someday to increase the ratio and speed of the fan, but the problem is needing airflow when there isn;t any..that is when sitting still..
ryan

Bobboloo · Bobboloo's Garage

So am I correct in that it can used to top off R-134a.

PatrickB · PatrickB's Garage

I'm wondering the same thing Bobby... I've got 134a in mine too, and a slow leak that requires the system to be refilled every 2-3 months... Prior to switching from 134a, the r-12 had to be topped off every 6 weeks or so, but was definitely colder... I was wondering if this stuff is colder than 134, and 12... Would it be better to flush out all the 134a & run this instead?

Bobboloo · Bobboloo's Garage

Patrick,

Evacuating makes more since when you think about. I don't know why I said top off anyway considering there isn't much if any 134a left in my system. What I meant to really ask is if it can be used without changing the lubricants in the system. That's what I was gleaning from reading the specs anyway.

ChrisM911SC · 07-21-2005, 07:41 AM

The answer is yes; it is compatible with both R12 and 134a. The manufacturer also claims that it is up to 32% more efficient than both R12 and 134a. And for those of you with slow leaks, it's ozone friendly.
It can be used to top off a system, but I would definitely use gauges if you have access to them to prevent over charging. 5 oz = 13.3 oz 134a.

Kurt B · 07-21-2005, 08:10 AM

Wow...compatible w/ both. So to use the right gauges---> I have a setup with 3 lines. A fill line and two others each with gauges. I suppose I fill up the lowside and measure the pressure on the high side until the pressure's correct?

ChrisM911SC · 07-21-2005, 08:37 AM

Kurt, if your system is completely flat you can measure the amount of the initial charge simply by knowing how many ounces you have put in. I know the SC models with factory air hold 47 oz of R12 (Bentley manual). The middle (yellow) hose on your gauges is for charging and the (blue) low side is for measuring pressures. If you can get the low side hose connected to the low side on the compressor while it's still in the car you can read pressures with the system running. Typical gauge readings should be between 32psi and 42 psi at 80 degrees. Mine read 47psi at 110 degrees outdoor temp.

Joeaksa · 07-21-2005, 09:10 AM

Quote:

Originally posted by ChrisM911SC
Joe, could you let me know where the local supplier is? 38-40 is unbelievable. Normally 56 is a good output for auto AC.

edit; Joe, which compressor are you running?

Chris,

I am using the stock rotary compressor that came with the '85 911.

Believe the guy selling the gas locally is : autocoolrefrigerantsAThotmail.com . (replace the AT with @) Name is Terry DeFalco and tell him Joe from the Jag group sent you.

JoeA

ChrisM911SC · 07-21-2005, 09:14 AM

Thanks Joe.

PatrickB · PatrickB's Garage

Quote:

Originally posted by Joeaksa
Outlet temps on my "airport car" have been in the 38-40 degree range, and thats excellent in Phoenix when its 110 outside.

Joe A

Jeez Joe... 38-40 at the vent? I'd be spending my Arizona summer's in the car, not the house!!

yeuporsch · 07-21-2005, 11:29 AM

Read this.

http://www.vasa.org.au/pdf/hydrocarbons/maclaine-cross.pdf

John

ChrisM911SC · 07-21-2005, 11:50 AM

Wow. I'm not sure if this stuff contains propane, but I'll get the MSDS sheets on it. Wouldn't R134a do the same thing? It has a lower flash point at 0 psi 1411 F, and a much lower flash point at 5.5 psi 368 F. The hydrocarban retains the same flash point 1585 F at 0 psi or 5.5 psi.

Kurt B · 07-21-2005, 11:55 AM

Sorry to belabor this...just want to be clear since I just had a new compressor put in and the lines flushed. If I get some of this stuff, and let's say there's a small leak that takes a few months to be noticeable, can I top off with this stuff without evacuating the whole system, or will I get pressure-creep where everytime I top off, the overall pressure of the system continues to grow until, i can't top it off anymore. It's all just air in the system?
Thanks.

ChrisM911SC · 07-21-2005, 12:01 PM

Kurt, if the system is not pulled into a vacuum state, it is very difficult over charge it. The differences in the refrigerants is the weight. If you do top off, your system will basically tell you when it's full because it won't accept anymore gas.

Jim Sims · 07-21-2005, 12:03 PM

http://www.autoacforum.com/MACS/HCwarning.pdf

PatrickB · PatrickB's Garage

Quote:

Originally posted by yeuporsch
Read this.

http://www.vasa.org.au/pdf/hydrocarbons/maclaine-cross.pdf

John

John.... Where did you find this?? Very interesting!
I'm no rocket scientist, or even an engineer for that matter.... Just a guy with, hopefully, better than average common sense!

That link unveiled a rather frightening, and very unscientific engineering experiment gone horribly wrong! Who would ever put themself in an enclosed environment, fill with a gas, and then light a match to test flammability, or lack of?? This guy gets my vote for the Einstein award for the year!! IMO, this was a very flawed test, totally lacking any credibility... I suppose a lab rat would get cancer after consuming nutrasweet in an amount equal to its body weight daily for a year. Does that mean if i consume 1 packet a day in my morning coffee, it will be the cause of cancer for me??

I'm always suspicious of a new product, when it sounds too good to be true... I'm sure the stuff works well, and will more than likely run it in my ride if I can purchase it online...

From Chris' posting of the specs, it does appear to be almost 4 times as flammable than 134a? I have to question the likelihood of the material in the sytem ever being exposed to an ignition source though... I had an aftermarket A/C system on a former car I had in the 80's, where fittings failed on me several times. The r-12 evacuated so quick, it looked like the radiator just blew the lid off of a car overheating. The point I'm trying to make, is that would probably be the necessary amount of refrigerant to cause an explosion when properly exposed to an ignition source. Any minor leak in the system would probably not be enough to ignite an explosion

ChrisM911SC · 07-21-2005, 12:23 PM

Patrick, just the opposite on the flammability. R134a is almost 4 times as flammable as the hydrocarbon at 5.5 psi. Still, these are both disturbing articles. As I stated in my original post, I thought I'd give it a try. Might be time to breakdown and do the R134a retrofit.

Does anyone have any data on R134a having similar risks?

PatrickB · PatrickB's Garage

Sorry! I always get those flammability/ignition numbers backwords... If that is in fact the case, wouldn't 134 be 4 times as ignitable as es-12?????

The es-12 product should be far safer in theory then.... Right??

PatrickB · PatrickB's Garage

Jim~

If the specs that Chris accessed are indeed accurate, 134a should be banned as it would be far more likely to cause an explosion than r-12 or es 12.....???