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Old 07-12-19, 10:37 AM
  #26  
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There's also going with R-152a (Dust-Off) - works great as a drop-in R12 replacement, but it's a DIY only option. I've done a few cars with dust-off and have been satisfied with the results.

I know the 134a cars have a compressor that says "134a" on the back. I don't know what all changed with it or if it was just pre-loaded with the proper oil.

Dale
Old 07-12-19, 10:44 AM
  #27  
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Originally Posted by DaleClark
There's also going with R-152a (Dust-Off) - works great as a drop-in R12 replacement, but it's a DIY only option. I've done a few cars with dust-off and have been satisfied with the results.

I know the 134a cars have a compressor that says "134a" on the back. I don't know what all changed with it or if it was just pre-loaded with the proper oil.

Dale
I'd be curious to see what is actually different from the R-12 Denso system and the R-134a Denso system in the FD. I'd guess they're almost the same with just some minor revision changes; If they're not, perhaps we could document what to upgrade?

I may do some digging in the part catalogs.
Old 07-12-19, 10:51 AM
  #28  
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I think a lot of the AC parts are NLA at this point, but the parts catalogs may shed some light as to what parts were revised. But, some may be the same, such as the driers, but the 134a version may be pre-loaded with the 134a oil instead of mineral oil. I imagine when they are installing them at the factory they have the driers and compressors pre-loaded with oil.

The lines would be interesting, I imagine they would have had to upgrade to the barrier hoses.

I know Mazda did a TSB sort of thing showing the new O-rings for all the AC fittings to the "green" o-rings that are 134a compatible. They work with any refrigerant, though.

Dale
Old 07-12-19, 11:23 AM
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I made a new thread to not go too far off topic here.

https://www.rx7club.com/3rd-generati...stems-1137448/
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Old 07-14-19, 06:53 PM
  #30  
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Quick question.

If my car came equipped with MANA. Is it possible to take everything out and do a complete swap to Denso?

Will the harness and all under the dash connect up pnp?
Old 08-08-19, 10:29 AM
  #31  
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I'm officially rescinding my endorsement of the envirosafe ES12a HC refrigerant, so please ignore the recommendation above. I always charged with traditional refrigerants when I did it professionally, but tried the alternatives on this car after reading success stories on forums.

After struggling several seasons to get decent vent temps in the 7 with ES12a I finally decided to put some real refrigerant in the car. Results were positive and immediate. It blew mid 40's from the vents with half a charge and was getting 39F vent temps with 21 oz of the good stuff (what the 1993 car came with). Sight glass cleared at full charge. 30 psi low 175 psi high at idle.

I am reasonably certain that the same results could be had with R134a or even R152a (duster - there's a great thread on it in the FC forum). I would have tried those, but I have mineral oil in my system and didn't want to pull the compressor to drain it. You need PAG oil for those refrigerants. We always used the mineral oil compatible BG Frigiquiet R134 oil at our shop and had great results from conversions.
Old 08-08-19, 12:50 PM
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Originally Posted by Copeland
I converted my Denso system to R134a with PAG oil and it's plenty cold. I don't get 38F vent temperatures but they're comparable to modern R134A cars.

I'm interested in seeing what an R12 equivalent would be compared to my current setup.
I should update mine as well, I don't get 38F vent temperatures. I get 37.9F vent temperatures

95F ambient temperatures

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Old 08-09-19, 10:52 AM
  #33  
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Originally Posted by ItalynStylion
Well I went to a local place. Super small shop, 1 really old dude who ONLY does AC service. Anyway, I went and told him what was up and we charged the system and included some UV dye just in case. It blows a lot colder now and doesn't make as much noise.

Additionally, we were looking at the running engine while the system was charging and he said, "You know what, I'll bet the other guy was looking at your air pump." (mine isn't functional). And we both started laughing. I don't know what's worse, the guy from FireStone lying to me about my compressor not working or him being honest and not knowing which one was the compressor.

Anyway, end of job, thanks everyone for the help!

Since I'm in North Dallas (Allen), out of curiosity which shop did you take it to?
Old 08-10-19, 01:19 AM
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Originally Posted by alexdimen
I'm officially rescinding my endorsement of the envirosafe ES12a HC refrigerant, so please ignore the recommendation above. I always charged with traditional refrigerants when I did it professionally, but tried the alternatives on this car after reading success stories on forums.
I tried all three on mine for the fun of it (and to verify I got all the leaks/problems on my system taken care of before I put anything expensive in it). I didn't write down the temperatures I saw, but I can say in the Texas heat ES12 was noticeably warmer than 152A or 12. ES12 performed fine until it was over 90-95 outside + humid, so I guess for some climates its alright.

It's harder to call between the dust-off stuff and 12. I think 12 won at idle noticeably, but dust-off did ok at idle, and was pretty good once the rpms picked up even a little. I know there are some good write-ups on here that go into detail on the differences. If I remember right, it pretty much lined up with what I noticed.
Old 08-11-19, 06:46 PM
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Originally Posted by eslai
I got my R12 system repaired in 2017. Had to replace the evaporator, expansion valve and dryer. It took some work to find a good shop that I could trust that would be able to do an R12 fill, but I think it was worth it rather than switching to R134a. The system blows VERY cold.
Did you find this shop in San Diego? I'm looking to recharge mine as well.
Old 08-12-19, 07:20 AM
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Originally Posted by dfwrx7
Since I'm in North Dallas (Allen), out of curiosity which shop did you take it to?
This dude (I think his name is Marion?) got me running right. It's literally just one guy and a bit of a janky shop but he was extremely nice and really knew what he was doing.

https://goo.gl/maps/jbpPr8w1TPq4YCkW7

2630 Northaven Rd #107, Dallas, TX 75229
Old 08-16-19, 10:12 AM
  #37  
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Originally Posted by Copeland
I should update mine as well, I don't get 38F vent temperatures. I get 37.9F vent temperatures

95F ambient temperatures


While these results are certainly chilling (knee slap), an AC performance test is typically done on the highest blower setting. Get 37* on speed 4 and I’ll really be impressed, and probably suggest wearing a sweater in your car.

*update*

Drove mine today. 107*F ambient here in Phoenix and my R12 system was putting out 50*F from the vents on blower setting 1 and 65* on blower setting 4. Not the greatest. I have a Greddy V mount so the condenser sees a bit more airflow than a front mount.

Matt

Last edited by Mrmatt3465; 08-16-19 at 05:50 PM.
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Old 12-11-20, 06:19 AM
  #38  
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Originally Posted by Mrmatt3465
While these results are certainly chilling (knee slap), an AC performance test is typically done on the highest blower setting. Get 37* on speed 4 and I’ll really be impressed, and probably suggest wearing a sweater in your car.

*update*

Drove mine today. 107*F ambient here in Phoenix and my R12 system was putting out 50*F from the vents on blower setting 1 and 65* on blower setting 4. Not the greatest. I have a Greddy V mount so the condenser sees a bit more airflow than a front mount.

Matt
LOL, how do you even survive in your car with 37 degrees? Is it even possible? You need to get an AC as fast as possible, you're getting cooked alive in your car. My dad's old Ford also had no AC, he was wet every time when he drove that car in the summer time, until once I decided to make him a surprise and called the guys from Aircon Servicing. They did a great job, a smooth and fast installation and now the temperature inside is perfect. Driving the car in 40 degrees is not a problem anymore and I am no longer aware of my dad's safety when he drives in this heat.
Old 12-11-20, 10:45 AM
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Originally Posted by Stewwow
LOL, how do you even survive in your car with 37 degrees? Is it even possible? You need to get an AC as fast as possible, you're getting cooked alive in your car. My dad's old Ford also had no AC, he was wet every time when he drove that car in the summer time, until once I decided to make him a surprise and called the guys from . They did a great job, a smooth and fast installation and now the temperature inside is perfect. Driving the car in 40 degrees is not a problem anymore and I am no longer aware of my dad's safety when he drives in this heat.
I think he was getting 37F out of his vents, not 37C (99F)

40C (104F) is a death wish with no AC. That's getting close/into the temperature range where even on a motorcycle completely naked you would be liable for a heat stroke eventually. The air simply is too warm to effectively cool your body. Add the reduced airflow and greenhouse effect of a normal car cabin and that's playing with fire. Add the heat that our engines produce and you're basically just roasting yourself.
Old 12-12-20, 04:25 PM
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i have my own stash saved so I haven't purchased any from Napa so I can't be certain if they actually have it or can get it...... but anyone on here desperate enough for it and willing to pay for it with along with an epa license can try. On napaonline.com it does show some stores that has R-12 can for pickup or at least get it within a few days. It's pricey at $62 a can but I'm sure there are some who will pay for it to get the desire temperature output from their a/c
Old 12-14-20, 01:16 PM
  #41  
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I've bought vintage cans of R12 off Ebay before, you do need an MVAC certification to buy it (I have that) but it's another option. I've found cans for a good price in the past. Not sure what they are going for now.

Dale
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