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Its super hot here in the deserts of the southwest... Looking to improving the performance of the AC system. Some say bypassing the heater core will help the AC perform better.

Any opnions?

It never freezes here, almost never ever use heater, there isnt much humidity so defrost mode is never used either...

Thanks.
 

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Without going into a full system rebuild, keeping what you have topped off and clean would be the only things you can do. Bypassing the heater core shouldn't affect the ac system since it should have a valve that closes off flow to the core when its not being used anyway.

E.t.a. if you haven't already, tint your windows with a good ceramic tint to help block radiant heat. Of your ac system is in good condition, mitigating how much heat is being absorbed would be my next step.
 

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just a quick fact, a proper operating A/C system can only cool approx 20 degrees Fahrenheit difference between ambient outside temp and the air coming from the vents. ensure airflow is happening (cabin air filter is clean) keep in mind the air inside the car is what's used to add heat to the evaporator to assist in changing the state of the freon and subsequently cooling the air coming into the car.
all the above ideas are a good compliment, sometimes the A/C will work more effectively at 1/2-3/4 fan speed than full blast as well.


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just a quick fact, a proper operating A/C system can only cool approx 20 degrees Fahrenheit difference between ambient outside temp and the air coming from the vents. ensure airflow is happening (cabin air filter is clean) keep in mind the air inside the car is what's used to add heat to the evaporator to assist in changing the state of the freon and subsequently cooling the air coming into the car.
all the above ideas are a good compliment, sometimes the A/C will work more effectively at 1/2-3/4 fan speed than full blast as well.

Mostly true. However when in recirc mode, your cabin will always cool faster at max fan. All other theories are myths. When pulling in air from outside, there is a balance between max air flow with medium temp vs min airflow with cooler temps at the duct due to the fact that you can only take some much heat out of the air in a single pass. But, that doesn't apply in recirc mode.

Also, I've put temp gauges all over my AC system in my '09 with the same goal as the OP (Texas can get stupid-hot as well). I found that our systems can take a little more than 30 degrees F out of the air when the humidity is low. The real trick to good AC performance is to get it into recirc mode fairly quickly but first tilt open the sun roof to let the scalding hot air exit when you first get in. After a minute or so, you can close it and just stay in recirc mode until you are nice and cool. I've been researching some zeotropic refrigerant alternatives to try to improve heat transfer performance across the evaporator. Pure propane is an interesting additive to an ac system. So is mixing in other specific freons. The whole effect is greater than the sum of the parts when mixing them. If I get any meaningful data before I completely destroy my system, I'll post up the results.
 

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Id check the system is working correctly, its regularly 115*+ here in Dubai and I can easily cool the interior down to 75*
 

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Mostly true. However when in recirc mode, your cabin will always cool faster at max fan. All other theories are myths. When pulling in air from outside, there is a balance between max air flow with medium temp vs min airflow with cooler temps at the duct due to the fact that you can only take some much heat out of the air in a single pass. But, that doesn't apply in recirc mode.

Also, I've put temp gauges all over my AC system in my '09 with the same goal as the OP (Texas can get stupid-hot as well). I found that our systems can take a little more than 30 degrees F out of the air when the humidity is low. The real trick to good AC performance is to get it into recirc mode fairly quickly but first tilt open the sun roof to let the scalding hot air exit when you first get in. After a minute or so, you can close it and just stay in recirc mode until you are nice and cool. I've been researching some zeotropic refrigerant alternatives to try to improve heat transfer performance across the evaporator. Pure propane is an interesting additive to an ac system. So is mixing in other specific freons. The whole effect is greater than the sum of the parts when mixing them. If I get any meaningful data before I completely destroy my system, I'll post up the results.
there is a reason propane isn't used.. unless you like the idea of the flammability issue if in an accident. it does work though, was quite common for many years until the new refrigerants have come into play. I haven't experienced any gains from recirc mode with mine, although max temps here are 35 Celsius if we are lucky lol. I usually roll the rear windows down a touch and let it air out then seal it up and it cools down pretty quick.


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there is a reason propane isn't used.. unless you like the idea of the flammability issue if in an accident. it does work though, was quite common for many years until the new refrigerants have come into play. I haven't experienced any gains from recirc mode with mine, although max temps here are 35 Celsius if we are lucky lol. I usually roll the rear windows down a touch and let it air out then seal it up and it cools down pretty quick.


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I love the logic that the 2-3lbs of propane are flammable in an accident yet we carry 100+ lbs of gasoline in our cars. And believe me, gasoline is way more dangerous than the bit of propane that would be used in your AC. Not to mention that there are a bunch of vehicles (especially in Canada) that have been converted to run on propane. Why is it suddenly more dangerous in your AC sealed up tight than it is being fed into your engine? Which one do you think is more likely to leak in a collision?

The real reason propane has been outlawed for use in mobile AC units is because the chemical companies that hold the patents on the various approved Freons have always lobbied to make their product the only one legal for use. I don't blame them -- if I spent millions on developing a specific mix, I wouldn't want something as simple as propane undermining my efforts.

Anyway, not meaning to argue. I just wanted to point out how silly the arguments against using standard hydrocarbons is.
 
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