which refrigerant?

[engine]

I'm planning an A/C upgrade on my Camaro (original A/C car). I installed new Delco evap and condenser the last time the engine was out. So now I have to get the compressor. I'm going to go with a Sanden/Seltec compressor, but haven't totally decided on which refrigerant to use.
When I first planned on installing the A/C, I figured I'd use R12 since I have a considerable stash of it. But now, I'm second guessing that for the sake of, "what if I run out"?
Problem is, my brand new un-used condenser is a fin/tube type, designed for R12. The condenser came with a tag that says, "For use with R12 or R134a Only. The use of any other refrigerant will void all warranties. If R134A is used, an auxiliary electric fan must be installed."
So this raised an eyebrow and I did some homework. Seems that R134A is best utilized with a parallel flow condenser with more surface area for heat extraction. My fin/tube unit isn't the best for it, and this will probably cause higher head pressures and less cooling effect.
I have already installed the Mark VIII fan and DC controller, so I'm sure I have enough cooling capacity to keep pressure down, but the condenser may still be inadequate.

So this brings me to ask, what would you do? I really don't want to spend another $200 on another condenser...

[cykotic]

Isn't R134a more readily available. Seems you can just go and get it at walmart if need be. That's enough to make me want to switch over. I think the R12 you have to get from licensed shops or whatever. I could be wrong.

[BADVELLE]

I would recommend staying with R12 as long as possible. It is my experience that you get a cooler air from the R12, as opposed to the new R134A. You can always switch over in the future, if you run out of your stash.

[engine]

Isn't R134a more readily available. Seems you can just go and get it at walmart if need be. That's enough to make me want to switch over. I think the R12 you have to get from licensed shops or whatever. I could be wrong.

I am licensed and have an account with a licensed shop. And my stash is about 90 lbs...

[CDJr]

Sounds exactly like my situation, engine (except my stash is only about 20-25 lbs) lol. But Im definitely gonna use R12 in mine. Itll cool better, and you probably wont have leaks on your new system, so I doubt youll run out.

[toxicz28]

If R134A is used, an auxiliary electric fan must be installed

Throw a fan in front of the condensor to kick on only when the a/c is running.

[gearbanger]

I this new R12 freeze was compatible with R12? If that is the case, then just use R12 until you run out and then start putting R12 Freeze in it.

[Madspeed]

I know you have a stash of 12 but when you run out its gonna KILL you to buy it again or change over to 134
If you switch over you will need a compressor and acumilator then flush out the system, So how much will all that cost compared to selling a couple LBS of 12 to cover the cost of a new condensor?

134 is $13 #
it doesnt make sense to use 12 the difference Isnt much in cooling
do the system 134 and do it right and the results will speak for themselfs
I to have a Lic to buy and service ac but I wont use 12 in my systems not when it cost $500 + for 30 lbs

my .02 c

[LS6 Tommy]

I've been in the HVAC industry for over 20 years and have both mobile and Universal certs. You only lose about 12% capacity over R12 on a proper 134a retrofit, and ASHRAE is now saying that the 134a is more or less a drop in. They no longer feel that a total system flush and lube replacement is necessary as long as you do a proper recovery of the R12. They came to the conclusion that so many "DIYers" have been doing without a flush/oil change without long term problems that it might not be as critical as they once thought.

Tommy

[engine]

Well, my real question I supposed would be, about the condenser I have.

I picked up a new Delco condenser, which happens to be a copper fin/tube factory replacement unit.
I have read that when using R134A, you really should go with an aluminum parallel flow condenser which has considerably more surface area for heat extraction.
I'm just worried that with my fin/tube condenser, I may not see good efficiency with R134A, as well as higher than normal head pressures.
Anyone using 134A with a stock old technology condenser? how is it working for you?

I'm in the Commercial HVAC industry for 7 years now...mosly work on Centrifugal chillers these days.

[gmachinz]

Engine, you won't have as much of an issue with the retro-fit as you think. I've performed many R134 retro-fits and the biggest difference is that R134 moves at a slightly higher pressure than R12 did which means less time for heat transfer through the condensor which is why they make the note about using an electric fan. The Mark VIII is more than up to the task and just so you know, we will be testing a new AC probe that will measure liquid line temperature and adjust fan speed using that info along with engine temperature, too. Fill your system to 90% capacity and you'll be fine. Oh, and replace/clean your expansion valve, too. -Jabin

[engine]

Engine, you won't have as much of an issue with the retro-fit as you think. I've performed many R134 retro-fits and the biggest difference is that R134 moves at a slightly higher pressure than R12 did which means less time for heat transfer through the condensor which is why they make the note about using an electric fan. The Mark VIII is more than up to the task and just so you know, we will be testing a new AC probe that will measure liquid line temperature and adjust fan speed using that info along with engine temperature, too. Fill your system to 90% capacity and you'll be fine. Oh, and replace/clean your expansion valve, too. -Jabin

OK, I'll try the 134A, but the system is ALL new, so I won't have to flush anything...

[gmachinz]

Cool-if it's all new, then just throw it in a vacuum until you can pull 28-30 inches, then if it holds with pump off for at least 3 hours with no drop in vacuum, I'd say you're good to go! -Jabin

[engine]

Cool-if it's all new, then just throw it in a vacuum until you can pull 28-30 inches, then if it holds with pump off for at least 3 hours with no drop in vacuum, I'd say you're good to go! -Jabin

I actually like to pull vacuum to 500 microns or deeper. But with Automotive AC rubber hoses, I'm not sure if that is possible. I may get there, but I'm not sure how "non-permeable" the hoses actually are. But I guess if I'm under 1000 microns, it's good enough.