I have a 77 L-48 Auto. The A/C system is pretty much all new = compres,hoses,VIR,vacum switches and levers. I just took the A/C box off and cut then fiberglassed it bigger to place a C4 fan cage on. Fixed all A/C ducts, placed a bigger ground wire to the fan for increased speed. The only original part is the A/C radiator that sits inside the A/C box. I had the system charged a few months back with R134. But the air is not cold, like I'd like it to be. The coldest that it gets coming out the center dash vents is 61-62 degrees. Is there anything that I can do to get the air cooler? Any help please. Can my VIR be adjusted/calibrated??

 

http://forums.corvetteforum.com/c3-t...lacements.html

This an old post on what I did to get my system to cool. As far as I know the VIR system with 134 will never do the job. Mine could not cool properly with R12. Others have said they could get theirs to work but I never did. Make sure your diverter doors are closing too. You also need to make sure that no hot water is going into the heater. There are many other good posts on a/c if you search for them.

 

I have removed the heater. The doors that lead to the heater are perm. shut. I have the vent by the wiper's shut so no outside air is coming in. I have the inside duct open.

 

The vir won't work as well with 134 as it did with 12 as is. The poa has to be adjusted for an evaporator pressure of 26.5psi instead of the higher 12 setting.
Additionally a parallel flow condenser is also required for peak performance of around 50°F

Some people stay with 12 to avoid the hassle and depending on source, it can even be cheaper to do so. Reverting back to 12 from 134 is illegal so all shops won't do it.

 

What does a "parallel flow condenser" do differently then a regular one??

 

I have been running a stock compressor, VIR, and stock condenser with R-134a for quite a while with similar unsatisfying results. I am in the process of changing the compressor to a Pro6ten, installing a new cross flow condenser, and installing a VIR eliminator kit. I haven't gotten any replies from vette owners who have installed these same components, but I am hopeful that it will give me a reliably cold A/C system with R-134a.
I'll have more updates after I can work on it more this weekend.

 

Basically much more refrigerant is in contact with the tube to release more heat.
Here's an example
http://www.ackits.com/c/Parallel/Par...+Aluminum.html

If you want to look at one , all Chrysler products have had them for the last 10+ years.

 

How do you tell if you have one or not? Mine is fairly new and is the same size as the radiator itself. Here are some pic's:

 

Yours is the most inefficient type.
Click on the kink and enlarge the diagrams, good ones have tanks.

 

Thanks! I will be going outside and checking if it is actually the condensor that is at fault. I will have the car running with A/C MAX with a temp. gauge in the vent. Once I get a reading, Iwill then take my garden hose and runn water over the condensor. After a couple minutes I will re-check temp. If the temp. goes down then I know it's the condensor. At that point I will have to make up my mind if I want to get a new parallel flow condenser or place a fan in front of it to cool it off more. Can I replace the condensor myself? Or does it have to be done by a A/C shop?

 

Yup, that's it!! Once I allowed water to flow over the condensor, my Temp. reading dropped 4 degrees. That is with water flowing on one small section of the unit. So now i need to replace it with the parallel flow condenser. I hope I can do this myself......

 

On my '71 I'm running the factory evaporator, a Sanden 508 compressor, parallel flow condensor and an adjustable POA valve set lower for R134a. Even with R134a I will freeze the evaporator after a while so I added a cutoff switch from a late 70's chevy pickup that cycles the compressor when the evap starts to freeze. Vent temps are in the low-mid 40s.

 

So now I need to find a parallel flow condenser that will fit my 77. Anyone know of one?

 

I also have a '77 equipped as yours is. I tried all of the fixes, VIR eliminator etc and I finally got tired of R4 compressers and the rats nest of AC connections and got a Vintage Air unit. These are listed for oonly up to 76, but only differences between a 77 and a 76 and earlier are 1) the center cluster stack and 2) the HVAC controls. I solved the center stack by carving an adapter out of styrofoam, fiberglassing the styrofoam and removing the styrofoam (a little more to it, but not much). I designed this adapter/plenum with the two hose connections on the left side of the stack, which avoided the "Vintage Air Crush" behind the center stack. I solved the control problem by ordering Vintage Air's 3 **** billet control, blocked off the square hole from the original controls and mounted the 3 **** control. Please note that if you are doing this, the 3 **** controller uses a different computer than the one supplied in the kit, so you will have to special order.

Finally, to answer your question about the parallel flow condenser, I got mine from Nostalgic Aire in Tampa (google for website) and got the largest one I could (approx 15" x 27") and mounted it using the 2 original vertical rods from the original condenser. I used sone galvanized Z flashing, trimmed down the width, and fixed one side to the length of the original rods and used small bolts to fik it to the perforated channel on the two sides of the condenser.

 

I got my condenser from Old Air products. It is 14" x 27". I am planning to mount it this weekend. I had already realized that some type of "z" shaped stock was going to be needed to mount it, but have not looked for the material yet.
Do you have any pics of the flashing you used?
Where did you get the flashing?

Also, did you re-use the metal lines that go from the condenser back through the core support, or did you buy new ones?
If you re-used the old ones, did you have to bend them to fit?
How did you bend them without getting kinks?

Thanks

 

These systems never were real efficient even when they were new. I went back with the original R12 and it cools good. I have found that now days R12 has become easy to get. I have been buying it on my craigslist for between $10-20 dollars per can.

 

Sometimes it's cheaper and usually a lot easier.

http://miami.craigslist.org/brw/pts/2372599680.html

http://miami.craigslist.org/brw/bfs/2364486223.html

http://miami.craigslist.org/brw/cto/2353478995.html

 

Thanks noonie, but I'm gonna stick with my R134. Everything on my system is new. And since I was able to drop the temp. to 57 degrees from 61 quickly just by spraying water on the condensor, I know a new parallel flow condenser will do the trick. I just need to find one that fits my 77.

 

Hey Dave. Have you put gauges on the system to see what the pressures are running? My late model '77 does not have VIR. I do not know when they changed over. I believe VIR has a dryer under the pass. fender that can be taken apart. Mine has a welded shut dryer. Post a pic. of yours. mike...

 

Are you still running the engine driven fan? converting to an electric fan will pull more air thru your condensor giving you cooler air at lower speeds