Taijutsu

My 74 has been changer over to the new refrigerant. It does not seem as cold. I have a C4 blower motor and the usual upgrades. What else can I do to make "MORE COLD"! TIA
Rick

BSeery

Many people say that the 134a is not as cold as the R-12 refrigerant.

Not much that you can do about it. Make sure that the evaporator and condensor cores are clean of debris, make sure the pressure is right and make sure your radiator is cooling the engine correctly.

Other than that, insulate the cockpit area of the car.

OHSIXX

I have read in a number of places R-134a does not get as cold as R-12. My R-134a system keeps it cool, but by no means freezing; especially with my top.

isosceles

My compressor locked up on Saturday. I had retrofitted with R134 and it was not very cold. The old compressor never built up the right head pressure, about 175 was as high as it would get. I replaced it with a rebuilt compressor from Advance Auto. The hi side gets to 250. I haven't meausered the temp from the vents, but with R134 it is cold, even at idle.

77Dream

Try making sure the cockpit is sealed and not letting a bunch of hot air in. There was a post recently about hot air comming in from the engine down through the kick panels, do you have that problem? How good is the insulation under your carpet? If you havn't done it, try putting some of that reflectix stuff under there and that should help alot also. (im doing mine this weekend).

Your AC system should be able to do the job just fine (its a small cockpit), you just might have to cut down on the hot air getting in.

:cheers:

OHSIXX

I am thinking about changing my compressor. Does anyone have any good links to look around?

Skeets

there was a strand on the forum recently about different refrigerants... i think one of them was called Enviro-Safe, or something like that?? .. they claim to make the AC run colder, be compatible with r-12 & 134a systems, as well as not putting too much pressure on the compressor.

...... does anyone remember that strand???

BigBadRed

I thought I read somewhere that a converted system should have about 75% of the r12 level. So the r134a would be 1.5lbs instead of 2lbs. No doubt a new compressor would probably work as well

Larry B.

R134a is very sensitive to the correct amount. The low side needs to be 26-28 psi. @2000 engine rpm. Any higher and it is over serviced and will not be as cold. At 26 psi the temperature should be about 37 deg F. R134a works just as good as R12. The system doesn't really care which refrigerant is producing the 37 deg air.. As long as the pressure stays correct it will work. Now if you condenser is plugged or doesn't get enough airflow and it can't disapate the heat the pressure will go up. That's not the fault of the refigerant.

Michael Tucker

:iagree:

play with it a little
Mike

Rockn-Roll

When I first got the vette the A/C system was empty, so I just filled it with R134a just to see if it would hold the charge. It didn't really get cold...just not warm. It held for over a year, so I went ahead and removed the accumulator/dryer and drained the oil out of the compressor, had the lines flushed out by a shop, filled a new accumulator/dryer with oil and installed it, had the system evacuated by a shop, then I filled the system with 1 16oz oil/R134a charge, then several 12oz cans of R134a. The lowest measurement I have made on a 100ºF day was 40ºF out the vents, cold enough to keep me comfortable. One of these days I will install a new blower and see if I can freeze myself. I also have vacuum operated heater hose cut-off and isolator valves that keeps any heat from getting into the evaporator housing.

munday

i was in the home a/c business for some time between jobs a while back and learned a little. typically 134a is not colder than r12, but it can be as cold in a 134a system, not a retro.

also, don't smoke freon, it turns in to phosgene gas.
:mad

vetteguy75

I also am ready to replace my compressor...my clutch burned up about 45 days ago and had it replaced. I asked the mechanic if the compressor was OK and he said it was and only needed the clutch replaced. However, since then, I have burned and shreded 3 A/C belts, and the same A/C mechanic keeps telling me the clutch is OK and the compressor is OK....SOMETHING IS WRONG...obviously. I am taking it to another mechanic on Tuesday....any help or info before I go, will be greatly appreciated..... :banghead: :cry

Corvette ED

Could you tell me about these upgrades? Does the C4 blower motor fit without any mods? What other upgrades.

Thanks
Ed

OHSIXX

Taijutsu

I had the same problem! Turns out the AC was wired in such a ways that it wouldn't cycle and burned itself up! I kept burning belts too. He went through 3 compressors. It was not a big deal to fix once found.
As to the "usual upgrades" they are all in the book . The gist is get a 3/4" spacer for the C4 blower motor. Put on/off valve in heater hose to stop hot water from entering cabin. Plug up all holes allowing heat in or cold out. Those are the big improvements. Who can test the output of AC compressor. I'm sure mine is weak. What could I upgrade to? Any thoughts?
Rick

flynhi

OHSIXX,
I have a radial compressor with brackets and hoses for sale. It has been used with R-134 and worked fine.
will_shepherd@hitmail.com

cheese

I had the same problem. Turns out the belt was getting down too far in the clutch pulley. Went with the next size wider belt from NAPA. Problem solved. Hopes this helps.