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My BMW can't even get that low and the system is working "perfectly" according to BMW. Asked on forums and they are all saying about 30 degrees below ambient is as good as the system can do. American cars may not be as reliable but at least they know how to make an AC system that cools the occupants.
Lol!!
 

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My BMW can't even get that low and the system is working "perfectly" according to BMW. Asked on forums and they are all saying about 30 degrees below ambient is as good as the system can do. American cars may not be as reliable but at least they know how to make an AC system that cools the occupants.
You need a better BMW dealership/mechanic. Temperature output needs to be in that range to pass BMW CPO inspection. I've owned 3 e46s and they all blew super cold. Just recharged my ZJ to get it back to that level of cooling.

To the OP: Nice work! My YJ was a 4 banger so it wouldn't have been able to move with AC! It could barely get of it's own way with 31" tires on it.
 

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My BMW can't even get that low and the system is working "perfectly" according to BMW. Asked on forums and they are all saying about 30 degrees below ambient is as good as the system can do. American cars may not be as reliable but at least they know how to make an AC system that cools the occupants.
Many factory manuals have charts of specs and ranges and there is a good chance that there is documentation to support the 30* below ambient claim however most vehicles will perform better than that. In the early days of R134A that was definitely true that 30* below ambient was pretty dang good. The technology improved though. I know that the Acura RL that was built from 1995 or 6ish until 2004 was a cold mofo. It had a 2 stage condenser in it and those were real cold. R134 does not perform as well as R12 did. That is fact. Humidity really strains an AC system along with ambient temp and sun load. I am certain that you understand this. One of the things that is mind boggling about todays cars is how little of a volume of refrigerant it takes to charge one. Many cars are very close to 1LB of refrigerant. Maybe slightly more. Older stuff took probably twice the charge. A key to good operation is the condenser has to be able to turn the refrigerant from a gas back to a liquid and that liquid needs to be cooled enough that the compressor can pull it down to a low pressure. As a rule of thumb, you refrigerant pressure will coincide with its temperature. R12 cars were pretty dead on. If you hooked up a gauge to an R12 system that was fully charged and the car not running the gauge pressure would read just about dead nuts the same pressure as whatever ambient temp is. Low side pressures while running would also reflect evaporator temps pretty close. R134 follows the same principle pretty close but not as close as R12 did.

AC is one of those dark science things to most technicians. I hate to say it but the majority do not really truly understand the theory of how it works and thus cannot figure out or know the totality of an underperforming system.

AC compressor shaft seals all have some leakage, it is a nature of the design. R134 is very small molecularly and will actually seep through the porosity of the walls of the rubber hoses. Hoses were redesigned for 134 because of this reason. What this leads to though is systems that periodically need to be recharged. When they do get recharged, techs will automatically add a couple ounces of oil. If you had a rapid discharge, you will lose oil. In a gradual one, not so much. An AC machine will drain the oil that was captured during recovery into a gradulated type of cylinder to measure. Most techs ignore this. It is also not an easy task to measure how much oil was in a component when you replace it. Not all manufacturers really publish how much oil to put back in when you replace the specific component and a lot of techs do not know to even look for it. The point of this is that if the system has been worked on as far as component replacement or just periodic recharges, having a system that is overcharged with oil becomes a possibility and this really affects the ability of the system to cool. Oil overcharge is bad but yet an oil undercharge will eat up a compressor. So, guys take the path that is safer and commonly add too much oil.

BTW. To the OP. Sorry for the hijack. Nice work. I am considering one of their systems. If it cools in Hell Paso then it for sure will make my nipples hard in Michigan.
 
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