A/C performance & data collection

I'll get back to you on this when I get my car back from the shop. They are supposed to recharge the A/C.

 

Your A/C outlet temp is about 15F higher than it should be, esp at 50% outside humidity.

Q about test conditions?
Were you driving, or was the car sitting still when you made the meas't.

If sitting still, it should have had a BIG fan blowing into the nose to force air thru the condenser coil.

Does the system still use R12, or has it been converted to R134a?

 

I've always used a metal cooking thermometer, head like a 50c piece and 6" rod.
Let set on seat to get ambient temp then stick it into the a/c vent and fire up
the a/c and note drop after 5 minutes.

Seem to recall an a/c tech doing this many years ago...anyway-I note my 308
when working well using R12, a temp drop of about 30F. But with sun beating
on the car causing 'oven effect' raising car interior 10-20F above ambient which
means with the 308 a/c only gets just below ambient sun beating on the car and
90F outside never gets below 80F inside which is why so many complaints.

Best a/c is an open window at 80mph.

 

your problem is the 134.

R12 will blow colder in cars that were never designed for 134. Case closed. Period.

I have a soapbox as tall as the Sears Tower on the 134 subject... Last weekend I just RE-converted another car BACK to R12 and now it works again. I would rather have herpes than 134 in any of my older cars.

 

Wow, I converted our old 91 toyota to 134 with a $30.00 kit from AutoZone. Just blew a few cans of 134 through the system (don't tell the epa) to clear out the old stuff, charged it with gas and oil and it worked great. Not as cold as before but I would rather have a really bad paper cut than pay for R12

Dave

 

Exactly. You took the words right out of my mouth.

 

The one, the only, R12 baby!
aaahhhhhhhh!

 

About 10 years ago when Costco quit selling to anyone without a license,
I bought a 30# bottle of R12-closest I've come to buying illicit drugs.

Friend of a friend gave me a phone number to meet a guy at a shop after hours.
The guy left an unopened box in a back corner, let me examine the box but he
stayed outside. I returned, he turned his back and wanted 3 crisp bills and asked
that he drive away before I went after the bottle. The shop owner gave me a
small blanket to cover the box while putting it in my trunk. Still have perhaps
1/3 bottle left. There is no substitute without changing all elements in the system,
hoses, everything. I've done 134 retros and was never satisfied.

Anyone need a hospital grade vacuum pump? 1/4-1/3 horse w/gauge-clean and strong.

 

They are selling brand new cars and refrigerators in Australia and europe with propane refrigerant. Its far more efficient and SUPER cold. In accident research studies they found all the scare tactics about propane refrigerant to be mostly hype propagated by DuPont.

 

Paul,
That's very interesting. Which mfg's are now using propane?

I've known for many years that a Propane-Butane mix is an excellent refrigerant, better than R12. Also suspected that the relatively small amount of propane in an A/C system just wouldn't be a major hazard. After all, many aerosols, especially spray paints, now use propane as a propellant - go figure...

BTW,
There's a great A/C forum & information resource site:
The Automotive Air Conditioning Information Server
http://www.aircondition.com/

While R134a retrofits in the 308 are not as cold as R12, when done properly, the vent tmp difference between R134a & R12 is only about 3F - 5F. In a converted system, the amount of the R134a is very critical. A couple of ounces too much, or too little & the vent temp goes up by another 7F - 10F. IMHO, sub-optimal charge is the major cause of unsatisfactory R134a operation. Since the system will leak an ounce or so/year, it also means that topping off the charge must be done annually.

 

Although this doesn't help you but to give you a comparison between the two gasses;
When I first bought my car(308GT4) it had been retrofitted to R134a.The hoses had been replaced as well.I couldn't get temps lower than 48F and I checked everything possible.I decided to remove the R134a and regassed with R12.I now get around 37-38F.My next step on the to do list is to replace the compressor with a Sanden 7 stage rotary type for more efficiency.I would like to replace the condenser but I cant seem to find an aftermarket on that will fit

 

Yep, 134 just plain sucks in a previously R12 car.

It may work better with a bigger condenser but I doubt one is out there like that for us. I don't want cool air I want COLD air, especially in the deep south

 

make that in a BLACK car in the deep south...

 

Anybody try Autofrost (R-406A) as a direct replacement for R-12? The manufacturer claims it is actually colder at the vent than R-12 is and can be used in R-12 systems without modification.

Some info here, with a good PDF on the stuff... www.refrigerantsales.com (Sorry, I couldn't find a direct link to the PDF)...click on "Alternatives" then the Autofrost graphic and you can find more info. Interesting stuff.

--J

 

ClydeM,
An alternative to the fan: Those small rectangular vents are very restrictive. They pry out pretty easily & you'll be surprised at how much more cold air circulates with them out. I leave mine partially inserted so I can easily pull them out.

maurice70,
The York compressor can pump more than enough refrigerant to cool a much larger system than the 3x8s. The fundamental 3x8 (& your GT4's) A/C problem is the relatively small evaporator coils & the low airflow thru them. Your 38F temps with R12 are already telling you that you aren't getting enough air thru the system. At 38F vent, the evaporator coil is probably below 32F & likely to ice up. More airflow would remove more heat from the cabin by transfering more heat into the evaporator coil. The vent temp would rise some of course, but the total cabin temp would be dramaticly cooler.

It takes about 8 or 9 hp to run a 3x8 compressor at max capacity. While the Sanden will take a hp or so less than the York type compressor, the system won't produce any more cold air as the York can already pump the max amount of refrigerant thru the system. So what the Sanden upgrade $ will give you is a bit more miles/gallon & a small increase in hp with the A/C running.

I see maurice70 is already following it. If the rest of you are serious about wanting improved A/C in a 3x8, you should be following Rob Baylor's AC system upgrade thread:
I'm fed up with my 308's lack of AC!!
http://www.ferrarichat.com/forum/showthread.php?t=164367

 

What I am surprised that no one has mention is the fact that the car is hot already. This weekend we went to a car show in MS. Car sat in the sun all day long. Since I forgot to get a can of 134a at the store the ac was not working.(yearly charge of 134a) On the way to MS the temp at the vent was 110. After sitting in the 98 degree weather all day,(roof on windows down) on the way home it was 125. Usually in the past I've noticed that it is hard to get the vent temp below 60, with the ac on and the windows up at speed on the interstate. Even at 60 at the vent that is a 65 degree improvement over nothing.
To me it's not the that the ac does not work it is how hot the car runs. With the way the heater piping runs through the dash and no inslutation between the cabin and the front end, boy it gets hot, much less the fact that the coolant pipes run right down the middle of the car. Oh and how about a header in the back of your head. i would love to get a temp coming off the back window on a hot day.

The best thing I ever did for my car was put on the Hayden fans. It never overheats any more, but neither does it have good AC.

My 2cents
Kelly
(See Tommy and Verell I still lurk around here sometimes.)

 

If that is the same stuff as "Freeze 12" who makes the same claims, it's total bull****. I tried it. When the vents were not as cold as before (with 12) I checked and found out it is 80% 134. I was pretty upset with the guy who put it in considering I asked for R12. Long story short I had the SOB disassemble everything and start over with R12.

 

I am VERY interested in autofrost...If anyone can provide additional input besides the business marketing this product, I would love to hear about it.

Mike

 

Doc...seems like this stuff IS NOT the same as 'freeze 12' . on the site they did an "alternative refrigerant mineral Oil miscibilities' test... wherein the 'autofrost' was compared to other refrigerants including freeze 12. seems like autofrost did not seperate from the 'oil' and returned it back to compressor..
I am not an a/c tech or claim to be mechanically inclined, I am just reading what is in print. If I get favorable information here I will pursue it further locally.

 

FWIW...reading the PDF document on Autofrost, there may be an issue potentially with some York compressors because of the type of rubber seals used. They recommend changing the seals to neoprene to avoid development of leaks and give a contact to discuss further. May be worth a call to that person.

--J