Greg

I'm in the California desert which means we hit the triple digits pretty regularly (it's the end of December and we hit 80 degrees today) so a functioning A/C system is an absolute must. Re-doing the A/C system on my '73 and I'm going to go with the VIR eliminator so the 134 will work more efficiently. I'd like some input from anyone who has already done this conversion. I'd like to know (1) if you kept your A6 compressor without any issues (I'd like to keep mine). I plan on replacing the hoses as they are 44 years old, so I want to know (2) what else you found you needed to replace as part of the VIR eliminator job, (3) who did you buy from, (4) how was the fit and (5) are you satisfied with the end results? Thanks, Greg

lvmyvt76

all "O" rings, condenser, evaporator, new fan motor with the larger wheel(will need to make a spacer), new belt, keep R=12 freon in it(cools better than R-134), this should be a good start! I did not eliminate the VIR< cools great! I mean if you have the system open changing part of it, completely rebuild it where you never go back into it. AND have someone that knows car A/C, check for leaks and recharge the car correctly. You should never have to go back into it.

Rotonda

I live in South Florida. We have a climate similar to yours except humidity is much higher and temps are slightly lower.

I started on this project for my 77. It was a total b***h, and the more I read the less enthusiastic I was about the probable result. I finally bit the bullet and put in a Vintage Air system (this took some adaptation as VA only makes kits for 68 to 76). I have not been unhappy with the result, and I am glad to have put the work (and money) into such an effective system.

OldCarBum

My complete A/C system needs to be overhauled. I've researched the cost to rebuild the oem system and the fact that when done the old system is still the old system with little improvement except that it will blow cold air. I found that for a little more money I can swap over to the Vintage Air System that everyone has been extremely happy with.

Greg

Thanks for your input but our winter temps are like your summer temps. Most systems work fine in the high 70's low 80's. We run 40 degrees hotter here in the summertime than Missouri, so it puts a tremendous demand on A/C systems. I know A/C very well. What I'm looking for is feedback from someone who's made this particular change up to their Corvette.

OldCarBum

I grew up towing boats through Palm Springs, Desert Center, and Death Valley on my way to the Colorado River where like Palm Springs the day time temp would hit 127 and cool off to a nice 126 at night.
It shows you've been a member here for almost 20 years.
I'm sure you have read countless threads on how the OEM a/c systems can't cool our corvettes and battle the interior heat emitted into the interior from the engine compartment.
If not go through the countless threads and read the testimonials of forum members who have tried to rebuild the OEM system and how many were satisfied and those who have swapped out to the vintage air system and their satisfaction. You'll find many with both systems who are happy.
In Napa we get many days over 100 degrees. I have the OEM system and it is not sufficient for our heat and so I'm swapping it out for Vintage Air.

chevymans 77

Eliminating the VIR will not make the system more efficient, it actually does the opposite but adding the correct condenser (parallel flow) will help tremendously with 134a.

Neal

Greg

Brother, you know it!
Yes, I combed through a million threads here (and several other sites I'm on) without a clear answer on this one, that's why I posted. I don't know if I'll get the answer I'm looking for or not. I suspect I may end up going with Vintage Air as well but I'm holding out a little hope that maybe one guy has had success with the VIR Eliminator system on a Corvette without going VA.

Greg

I understand, but the VIR is not calibrated to work with 134. I've found some have tried adjusting the POA, with mixed results.

chevymans 77

The characteristics of both r12 and 134a are very close so no adjustment is need, they are both very capable of holding the evap coil at 32* F. with no issues.

Neal

Greg

Thanks Neal, but this is where the discrepancy starts to show up.
I'm finding that the guys who've kept the VIR have adjusted the POA valve by 1/4 to 1/2 turn counterclockwise to lower the evap pressure to 26.5psi from the 29.0psi setting for R-12 and then they find positive results.

Greg

Of course all this hinges on a re-doing the VIR, new seals, new desiccant, etc.

chevymans 77

There is no discrepancy, doing so drops the coil pressure which also drops the coil temps. The outcome will be the same for both r12 and 134a but will allow the coil to freeze up in certain conditions. The OEM pressure set point is set to allow the system to function correctly in most all conditions.

Neal

Greg

Neal, is there any data on-line to back this up that I can access?
I've found the same results in the past with converting to 134. The system works OK, but not great. I'm pressing for more info on the POA adjustment as well. The guys who've done it, swear that it makes the difference.

chevymans 77

134a's advantage over r12 is its ability to dissipate heat at a higher rate as it operates at a higher discharge pressure/temp creating a higher DT at the condenser (the need for a parallel flow condenser). There is little to no advantage on the cooling side of the system as they both have to maintain the coil temps at or above 32*F to keep it from freezing over. The VIR adjustment lowers the coil temps and will do so for both r12 and 134a so adjusting the pressure is not a 134a thing it will work for both but cause other issues.

If serviced correctly both will work very well but the system will work better with the VIR as it allows the system to adjust to the varying flow rates of an automotive positive displacement compressor (adjusts for varying engine speeds (idle to WOT)) which will allow for a more consistent temp across a wider range of conditions. it will do this better than the CCOT will.

Like i said before if you want to improve upon the system and it has been converted to 134a one of the best things you can do is add the parallel flow condenser.

Neal

dtamustang

8 or 9 years ago i rebuilt the whole system in my 72 , including adjusting the poa valve. i did not adjust it with the 1/4 -1/2 turn method , i actually adjusted it by pressure. i don't know if its still around but there was an automotive a/c forum that had a ton of good information. some guys that really knew their stuff. after the poa adjustment and a c-4 blower the results were better than i expected. the car is a big block that lives in florida so it gets pretty toasty with a marginal a/c system. the system is stock , running 134 and i'm happy with the results.

lvmyvt76

don't forget to check all the grommets in the firewall, insulate under the carpet, behind the door panels, and in the area behind the seats(including the top of that area) to help any A/C to work more efficient. The best A/C won't work as well if you have heat pouring in from the outside. Also, check the connections on the duct work under the car. The hot water valve needs to be check for operation, or the heater hoses bypassed to stop any problem there. I went completely thru my dash area, heater box, new condenser & evaporator and did all this I am suggesting(now my car is not in Cal or Fl ), but it has a great A/c and with a black interior to boot.
If you have already done all this, then forget what I have typed here and go on with your project, BEST OF LUCK!!!!!!

redwingvette

I made the mistake of using the eliminator a while back. I later changed the evap and accumlultor to the 78-80 one. The problem I had and lessened learned is the VIR is smaller then the eliminator can so the bracket did not work. I should have made a new bracket to hold the can. If you want to go with
the R134 the you need to change the condenser to a parallel flow one. They are much more efficient and will help with the cooling

7T1vette

I haven't read the whole thread, but here is my input to your initial query...

I would HIGHLY recommend that you get rid of the A6 compressor and go with a new Sanden unit--much more efficient, smaller (lighter weight), more reliable, made for R-134a.

The VIR eliminator merely replaces the complicated (but clever) VIR with a low pressure switch to turn off the unit if refrig gets low. Simple swap out...ONCE YOU GET THE VIR OFF!!!! I emphasize this because removing the VIR will be the most difficult task in this job. That upper nut is a bi+ch to get access for wrenches and there is NO room or leverage space. You don't want to damage the evap coil, so you have to be CAREFUL with the BFH!!!!

calwldlife

Interesting.
a quick look for a parallel condenser showed they are
Expensive. Any tips? 81