Late G Body AC - not that bad?

[ahendy]

Hey folks, I've just acquired an 88 911 coupe, which has an AC system that's been partially upgraded recently (new compressor and drier a few years ago, some hoses replaced with barrier), but is stock design in all ways. It's also still on R12. This was my first experience with a stock system, as my other car didn't come with AC and I added a CR electrocooler system to it myself.

I had it charged up and have spent some time driving around in sweltering Tennessee heat (97+ degrees), and am finding I'm blowing ~40 degree vent temps consistently and actually needing to turn the system down! It actually kept the cabin incredibly comfortable with no issue.

Granted - my car is white, and my windows are slightly tinted — but are all of the complaints about the 911 AC system mostly due to R134a being substantially worse in these systems than R12? I'm certainly planning to keep it on R12 as long as I possible can..

I guess I was expecting it to be terrible, and I'm pleasantly surprised with the results. A rarity these days..

[ahh911]

You have an 88.
My 81 stock system running R12A, even more efficient than R12, is that it's better than my 2003 bmw m3 and slightly worse than my 2002 VW passat. My wife's latest audi is on another level. Just to compare the cars over several generations.

The 911 loses out over 80 mph on highway as too much air I think enters the cabin, then it's just survivable ~ 88F with full sun, just don't move too much

Phil

[dw1]

ahendy, you are correct about the stock system and R12. Assuming the system is in good condition (notably good compressor seals) the R12 a/c system performs well. It certainly doesn't hurt that your car is white (btw, my '87 is black/black).

A stock system with r134a is "ok" at best - the lack of condenser capacity being the biggest problem. Barrier tubing helps, but the pre-1990 system just wasn't designed for r134a. As long as the air temp and humidity aren't too high, my mostly stock system can keep up (especially since I had the windows tinted a bit darker), but at the TN conditions you describe - no way.

Luckily, Griffiths Technical has solutions for our older cars.

Good luck keeping your car on R12. My car was converted to r134a some time ago because R12 was getting so hard to find, expensive, and fewer and fewer certified (R12 is limited to certified techs) a/c service folks wanted the hassle.

[RSTarga]

Yes my car even at the 100+ lately seen around here is also in the 40-50 degree range on R12.
R134 needs more condenser.

[darrin]

@ahendy -- I had a very similar experience with my '86 targa -- stock system would work great for the summer after a spring recharge. However, after a year passed, its non-barrier hoses (and potential other leakage points) would allow enough r12 to leak out that its performance/cooling capacity dropped significantly. Finally bit the bullet 3 springs ago and replaced all hoses with Griffiths barrier hoses and added his upgraded front condenser, upgraded evaporator and replacement compressor along with a r134a conversion. System still blowing as cold as it did after conversion was completed (though it's been a while since I stopped refilling my old system with r12, the new, upgraded components appear to do a slightly better job cooling, even with R134a, than the old system did with r12) and appears to be continuing to hold its charge just fine. SO . . . if your system still works after another summer's behind you, congrats! Otherwise, you might want to consider taking the route I took and replace the 'guts' of your system with upgraded/leak-free versions.

[GH85Carrera]

R12 is available, just very expensive.

I too have a white 911, but mine is a 85. Much smaller AC vents than yours. I got the stock system "tuned up" and working the best it could. Then I drove to Ft. Worth TX in summer. At normal driving speeds it was tolerable, then I hit rush hour traffic in 100+ degree heat. It just was pitiful, and I rolled the windows down. It works great, or OK at least at night, or below 90 degrees

The biggest flaw you will encounter is the hoses are non barrier hoses. They were actually designed to leak. When R-12 was 60 cents per pound, no big deal. It got the customer's to come in and get it charged and maybe an oil change or other service.

The cure is barrier hoses, or just expect to recharge it every spring.

Now with many thousands of dollars spent with Griffith's I have a 4 condenser system, new hoses, and a host of other upgrades. I can park in 105 degree heat for 45 minutes, and sit in a car that is 135 degrees, and be OK in 10 minutes, and totally comfortable with 37 degree air in the hottest climates.

Enjoy the cool air and drive it!

[aoncurly]

Refrigerant leaking is much more of an issue using R134 with R12 dated hoses. I ran some back of the napkin calculations and newer barrier hoses leak R134 25 times less than older 80's vintage hoses. So, yes, if updating to R134, switching to newer barrier hoses is definitely warranted. But if you're still using R12 in a R12 designed system, I'm inclined to leave it alone in my climate zone. I'm getting my stock 1981 AC system worked on now and they are using R12. I'll see how much it leaks after it's fixed and running.

[GH85Carrera]

You can certainly learn by doing. It will indeed leak the R12 over a year, and you will be recharging every year to keep cold air.

[porschedude996]

So what is a 16oz can of R12 going for these days (8/23)?

[ahendy]

I’m finding them for $25-40 generally. Pretty insane but I may start hoarding them..

[GH85Carrera]

R-12 is hard to find as it is a federal law restricting the sale and purchase of R-12 except to licensed professionals. It is not overly difficult to get the license, but finding a place that even stocks it is difficult. Like many things the government don't want sold, it is not spending much money to stop it.

Much like muffler shops that bypass a catalytic converter, only if they have a customer complaint do they get serious about it.

[Koizumi]

After years of using both R12 and R134… R12 leaks slower than R134 and cools better (stock hoses in my car, Griffiths Evap and fan which are very very highly recommended).

Envirosafe Industrial cools significantly better than both R12 and R134. And much less pressure in the system. Charge lasts a year but is inexpensive and easy to recharge.

For antiquated AC systems, this is my go-to

[aoncurly]

Originally Posted by Koizumi

After years of using both R12 and R134… R12 leaks slower than R134 and cools better (stock hoses in my car, Griffiths Evap and fan which are very very highly recommended).

Envirosafe Industrial cools significantly better than both R12 and R134. And much less pressure in the system. Charge lasts a year but is inexpensive and easy to recharge.

For antiquated AC systems, this is my go-to

Yes, even on Griffith's website, it says if you have a functioning R12 system using R12, leave it alone. I was getting vent temps around 37F with a 93F ambient before my stock rebuilt R12 York compressor crapped out on me. It's under warranty so they are fixing. Do you recharge your system on your own with the can of Envirosafe R12 and how many cans do you use? Did you get a set of gauges?

[ahh911]

Originally Posted by Koizumi

After years of using both R12 and R134… R12 leaks slower than R134 and cools better (stock hoses in my car, Griffiths Evap and fan which are very very highly recommended).

Envirosafe Industrial cools significantly better than both R12 and R134. And much less pressure in the system. Charge lasts a year but is inexpensive and easy to recharge.

For antiquated AC systems, this is my go-to

Looks like R12a? Second year running, haven't added yet, all stock system.

[Koizumi]

I’ve been using Envirosafe for more than a decade on various “older” cars that have stock 12 systems with great success.

I do use gauges for R12, R134 as well as the Envirosafe - which I believe is designated as ES-12A, so I think this is what “12A” is.

Here’s the rub: I’ve been using Envirosafe for so long that I really don’t utilize the gauge readings anymore. The reason why is because for coldest air temps, Envirosafe PSI is 34 which is equivalent to R134 31 PSI. This gives a 34F-36F vent temperature which is as cold as you can get without freeze-up. For the stock AC system (front condenser, deck lid condenser), you need 2x 8oz. cans of Envirosafe Industrial. That’s it. Please note that the Industrial variant is colder than the regular variant. And also note that it comes in 8oz. cans versus the regular variant in 6oz. cans. Very convenient.

I’ll be adding the Zims fender condenser soon enough, so obviously I’ll have to fine tune with a bit more Envirosafe and gauge. Either way, if you’re running a stock system, try out 2x 8oz. Industrial cans! I’m adding the Zims because it has a fan and stop and go traffic as we all know, is no bueno for the AC. And an extra condenser coupled with Envirosafe will undoubtedly keep things chilly in traffic.

Also, as mentioned before, the Griffiths evap and powerful fan also make a drastic difference in performance.