when it is done right.....

[rjjp]

Theres no physical way a ac system can get to 15F. The low pressure cycle switch is set for ~25psi to cycle in. Theres no way it can get down that cold.

Yes there is, with heavy modification (Refrigeration systems run on the same principal)... Way more than just wrapping the pipes, plus you have the issue that water vapor in the air would freeze to the evaporator.

 

[monkeyboi]

15* would defeat the whole purpose of the A/C. The evap coil has to be warm enough to not to freeze up and prevent airflow through the coil but cool enough to cause the moisture in the air to condense on the coil, thereby lowering the humidity of the conditioned air. 15* would make a block of frost out of the coil in no time on a humid day.

 

[itsacrazyasian]

Yes there is, with heavy modification (Refrigeration systems run on the same principal)... Way more than just wrapping the pipes, plus you have the issue that water vapor in the air would freeze to the evaporator.

Again with heavy modification. Then our HVAC system would be useless. The clutch cycle switch simply does not allow for such evap temperatures under normal design conditions.

with R12 evap core temp of 15F would be about 16psi on the low side
R134a at 16psi is about 33F

Now you can make R134A blow very cold, new ac systems do very well as critical charge low refrigerant capacity systems. But again these cars use a thermistor or evap temp sensor to monitor core temps and adjust a variable expansion valve or compressor displacement or the age old way of cycling the compressor.
you will never get the evap core temp below what the physical refrigerant can do. Also just because its 95F ambient outdoor doesn't mean the air coming from the evap is going to be 35F right away. A well functioning system in our trucks on a high ambient condition should drop air temp 30F across the evap on one pass. So if you jump in your truck and its 90F in the cab when you start, you should have 60F air out the vent once the system equalizes. This vent temp starts dropping quickly as our hvac units can move quite a bit of volume. Betcha you didn't know our HVAC (cooling capacity, not heating) is 20,000 BTU. Thats almost 2 ton of cooling capacity.

 

[itsacrazyasian]

15* would defeat the whole purpose of the A/C. The evap coil has to be warm enough to not to freeze up and prevent airflow through the coil but cool enough to cause the moisture in the air to condense on the coil, thereby lowering the humidity of the conditioned air. 15* would make a block of frost out of the coil in no time on a humid day.

exactly!

 

[ken74amx]

on a r12 to 134 conversion i can make it 15 degrees with no prob as the press switches are adjustable. I had a Chevy van blowing 10.2 degrees and still dropping when i got out because it was too cold and mind you it was 93 out that day. the only complaint i ever got was a chunk of ice occasionally falling from under the hood. freezers freeze things and still blow air so why can't your truck or car. Also on any conversion to 134 you have to adjust the pressures since the freon requires a diff press to work efficiently. Now Just wait until the new co2 systems to come out. 20000psi bomb under your hood!

 

[FordGuy100]

Here is what mine was at a week or two before my compressor took a crap. Outside temp was 90* humidity 30ish%

You must be registered for see images attach

It was actually cold enough that the glass would fog on the outside going down the road.

 

[damac]

Damn I just got mine converted over to 134a after I used all older parts that looked to be in good condition and flushed them. Put new orifice tube, orings in every connection with nylog, replaced the drier and evacuated the system under vacuum for 2 hours before starting the charge process.

Same temps as you and it is only blowing 55 out of the vents, doesn't even seem to drop much when on the freeway.

Did you use all of the original hardware or upgrade parts specifically for 134a?

Would love to know how you charge yours on the ac gauges, perhaps I didn't get the charge right

 

[FordGuy100]

That was charged at the shop. It was the stock system with a VOV new o-rings, and R134a compatible oil.

 

[zrexryder]

I like to keep it simple, I use mp39, charge it til my disharge air temp 45' and my suction line at the comp is beer can cold.

 

[hesutton]

Where the hell did you fidn someone to charge your truck with R12?

My father. He is licensed and has done A/C stuff for years when he's not working in the coal mine. He probably has 150 lbs of the stuff just sitting there in his shop.

Heath

 

[flareside_thun]

I like to keep it simple, I use mp39, charge it til my disharge air temp 45' and my suction line at the comp is beer can cold.

Isn't that for commercial refrigeration units?

My father. He is licensed and has done A/C stuff for years when he's not working in the coal mine. He probably has 150 lbs of the stuff just sitting there in his shop.

Heath

Ah, lucky you....I found out the other day my truck hasn't been retrofitted yet....then I remembered my buddy charged my system with 134A with some R12 adapters he had for his manifold gauges.....

 

[GRU]

i really need to find someone that knows air conditioning, that wont charge me up the butt either. my air works ok, just ok. i think ive got as much a problem with airflow as i do with cooling. just doesnt move much air.

 

[Dieselcrawler]

sucks you didnt say anything before the rally. coulda brought along my gauges and keg of 134.

 

[MidnightBlade]

I have air for about 10 sec then it's back to outside temp like right now

 

[MIDNIGHT RIDER]

I am far from an A/C expert; RSDL seems to be the ice-cold-air man around here.


I will relate a few things that I do know.

A lot of the guys over on the Dodge site have charged their systems with plain old torch-bottle propane and are getting ice-berg conditions inside the cab with less than a bottle of propane, maybe 14-ounces.



The wife's 1991 Dodge/Cummins had the entire A/C system completely replaced about five years ago --- EVERYTHING, hoses, condensor, evaporater, compressor, etc. ; filled with R134a.

She had decent cold air until recently, when she started complaining that it just didn't cool as well as it should.

I removed the factory-supplied vacuum-operated heater-hose cut-off valve and replaced it with a manual ball-type cut-off valve.

We are currently in the middle of a heat-stroke and, with this little modification, she is now seeing vent temperatures of 29* and it is frosting the insides of the side-windows.




On my 1985 Ford, I pulled the blower, removed the evaporator box, removed the cowl-vent, accessed the heater-core, and removed the kick-panels and those little access plugs behind them.

I filled three five-gallon buckets with debris removed from all these places.

The blower box was so full of leaves and twigs that I don't see how it even turned the fan.

The evaporator was entirely plastered with a thick wet horse-blanket mat of **** that was obviously causing the wet-dog smell from the vents.

After cleaning out everything, I could actually feel the air coming through the vents.




One other little modification :

Ford has never been known for strong blowers.

With the engine running and blower on HIGH, my tester showed about 8.5-volts at the motor-plug.

I added TWO relays, triggered by a single switch.

One relay is full alternator voltage HOT straight to the blower.

The other relay is a DIRECT GROUND, big wire and GROUNDed close to the blower.

With these relays energized, my tester shows a bit over 14-volts at the blower; almost double the voltage of factory-stock.

With A/C on MAX and the factory blower switch on HIGH, I can sort of tell that there is a fan in there somewhere.

I can flip a switch and turn the Leece-Neville loose on the blower and it will blow the cap off your head.


None of these modifications required any A/C expertise at all.