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  • AC Upgrade?

    Wondering if anyone has successfully updated their AC system in an early car and if so what they used and how satisfactory were the results?

  • #2
    It really depends on where you live. I have the dealer installed A/C, but with a new Sanden, R-12 and a front condenser upright in an Rs front spoiler + the engine condenser in a ducktail. . Works fine for me.

    Comment


    • #3
      Houston.

      Anyone tried the Griffiths stuff?

      Comment


      • #4
        Originally posted by Keller View Post
        Houston.

        Anyone tried the Griffiths stuff?
        I'm about to do one in an '87 and I've heard good things. But I don't think Griffiths offers a setup for the early cars.

        Maybe we can lure
        Frank Beck
        Banned
        Frank Beck out of Off Topic for a minute. He's always bragging about his AC skills and he does live on the surface of the sun.

        Comment


        • #5
          There are people a lot smarter than me but that's never stopped me before from sharing my experience. lol Bragging? Not even close!


          Assuming that you're starting with a factory Behr system here are the challenges:

          Insufficient fresh air flow across the condenser(s).
          Inefficient evaporator and too far away from the dash vents.
          Evap fan is inefficient causing low volume.
          Stock York compressor is way too large in cubic inches.

          A stock Behr system when operating at maximum efficiency in 110 degree heat will easily drive oil temp to 280 degrees. (I've seen 300+ which eventually makes mush out of a mag case.)

          The goal is simple: Increase fresh air flow to the condenser(s) and optimize components given the stock space considerations. Unfortunately execution is a completely different animal. In a perfect world on a stock car here are my suggestions:

          Rotary compressor no larger than 7". (We've used as small as 5" with good results.) Or a 6" York if you want a factory look.
          Griffiths evaporator, fan, and expansion valve. (The old school expansion valves these systems use are adjustable and you can play with pressures.)
          If you're hellbent on retaining the engine pre-heater (AKA rear condenser) it's mandatory to have a second condenser that gets lots of air flow (I.E: David's upright condenser in an RS spoiler.) The 70-73 cars that used the robust squirrel cage fan on the front condenser are much more efficient than the later ones however they use a sheet metal housing that's part of the fuel tank support.
          Install a Pro-Cooler. A wonderful device brought to market by Ron Maxwell decades ago. It's a freon jacketed pre-cooler.
          Replace all hoses of course and insulate ducting.


          If you're building a hot rod and unafraid to modify here you go:

          69-73: Single mastectomy of the left battery box and fit a 964/993 condenser and fan assembly. Earlier and later cars this area is open and available.
          Lose the engine pre-heater.
          Pro-Cooler.
          Efficient rotary compressor.
          Griffith's evap and fan or if you're really a cowboy mount some type of evap, fan, and expansion valve box closer to the dash. You want the evaporator as close to your face and crotch as possible. In this scenario it's not even necessary to run an aux oil cooler. If the stock rear condenser is used you'll most likely need one.

          Misc:

          Huge under body condensers like Performance Aire used to sell are worthless in very hot, dry climates. All they do is pick up heat from the asphalt.
          Rear wheel well condensers with fans are not horrible but generate much more heat than front mounted.
          Aways use R12. I couldn't care less WHAT anyone else tells you. You can expect a 4-8 degree vent improvement over 134a.

          Good luck.











          Old, white cisgender male oppressor.
          Influencer/Life Coach.

          www.beckseuropean.com

          Comment


          • #6
            Originally posted by Frank Beck View Post
            There are people a lot smarter than me but that's never stopped me before from sharing my experience. lol Bragging? Not even close!


            Assuming that you're starting with a factory Behr system here are the challenges:

            Insufficient fresh air flow across the condenser(s).
            Inefficient evaporator and too far away from the dash vents.
            Evap fan is inefficient causing low volume.
            Stock York compressor is way too large in cubic inches.

            A stock Behr system when operating at maximum efficiency in 110 degree heat will easily drive oil temp to 280 degrees. (I've seen 300+ which eventually makes mush out of a mag case.)

            The goal is simple: Increase fresh air flow to the condenser(s) and optimize components given the stock space considerations. Unfortunately execution is a completely different animal. In a perfect world on a stock car here are my suggestions:

            Rotary compressor no larger than 7". (We've used as small as 5" with good results.) Or a 6" York if you want a factory look.
            Griffiths evaporator, fan, and expansion valve. (The old school expansion valves these systems use are adjustable and you can play with pressures.)
            If you're hellbent on retaining the engine pre-heater (AKA rear condenser) it's mandatory to have a second condenser that gets lots of air flow (I.E: David's upright condenser in an RS spoiler.) The 70-73 cars that used the robust squirrel cage fan on the front condenser are much more efficient than the later ones however they use a sheet metal housing that's part of the fuel tank support.
            Install a Pro-Cooler. A wonderful device brought to market by Ron Maxwell decades ago. It's a freon jacketed pre-cooler.
            Replace all hoses of course and insulate ducting.


            If you're building a hot rod and unafraid to modify here you go:

            69-73: Single mastectomy of the left battery box and fit a 964/993 condenser and fan assembly. Earlier and later cars this area is open and available.
            Lose the engine pre-heater.
            Pro-Cooler.
            Efficient rotary compressor.
            Griffith's evap and fan or if you're really a cowboy mount some type of evap, fan, and expansion valve box closer to the dash. You want the evaporator as close to your face and crotch as possible. In this scenario it's not even necessary to run an aux oil cooler. If the stock rear condenser is used you'll most likely need one.

            Misc:

            Huge under body condensers like Performance Aire used to sell are worthless in very hot, dry climates. All they do is pick up heat from the asphalt.
            Rear wheel well condensers with fans are not horrible but generate much more heat than front mounted.
            Aways use R12. I couldn't care less WHAT anyone else tells you. You can expect a 4-8 degree vent improvement over 134a.

            Good luck.










            And That is why I put up with Frank., he really has so much practical knowledge. Same as Bob Jones, they know how to keep these cars running well and don't just resort to using the latest specialist kit of dubious value. They can also fabricate and machine, so few have these talents any more.
            Cut out this post and add it to your workshop manual, covers everything in A/C without having to read endless dribble on Pelican in endless A/C posts.

            Comment


            • #7
              Originally posted by flatsixer View Post
              And That is why I put up with Frank., he really has so much practical knowledge.
              Me too. That and because I can kick his ass on a basketball court.

              Thanks, Frank. Super helpful stuff.

              Comment


              • #8
                Frank Beck
                Banned
                Frank Beck somewhat related question....whatever happened to your project a few years back to manufacture "red" AC barrier hoses?

                Comment


                • #9
                  The short version is that the product didn’t meet my standards and I pulled the plug. It was an expensive and very frustrating exercise.
                  If you can’t do it right, don’t do it at ll.

                  Takeaway?

                  Be VERY thankful for people like Eric and others who get quality products to market.
                  Old, white cisgender male oppressor.
                  Influencer/Life Coach.

                  www.beckseuropean.com

                  Comment


                  • #10
                    Originally posted by JP View Post

                    Me too. That and because I can kick his ass on a basketball court.

                    Thanks, Frank. Super helpful stuff.
                    Ahem... you have a slight height advantage

                    Comment


                    • #11
                      Originally posted by Frank Beck View Post
                      The short version is that the product didn’t meet my standards and I pulled the plug. It was an expensive and very frustrating exercise.
                      If you can’t do it right, don’t do it at ll.

                      Takeaway?

                      Be VERY thankful for people like Eric and others who get quality products to market.
                      Well, I would dearly like a set, so was hoping for a different answer, but completely understand the challenges of trying to make them...and make them to the same standards that Eric and others have established.

                      I once made the decision to scrap an entire 20' container full of molded power cables due to some quality issues. That one still hurts.

                      Comment


                      • #12
                        I have a 1973.5 911T coupe that i use as my primary vehicle in the Los Angeles area. I bought it almost 20 years ago with that in mind but only relatively recently (a few yuears ago) did the work it needed to be useful in the summer. It had a Behr 2-condenser setup which was not functional, but all parts were present.

                        First I installed the front oil cooler kit from Elephant Racing because I did not want to see excessive oil temperatures while using the air conditioner. The support bracket for the oil cooler was made for later 911s and so has to be reworked a bit but otherwise the installation was straightforward. I can provide some tips on this if anyone is interested.

                        Once I was satisfied that was working well I proceeded with the air conditioning upgrade with the 4-condenser setup from Griffiths. The kit is made for a range of cars up through 1989 and i found that one or two things didn't fit quite as advertised, but only minor changes were required. This uses R-134a refrigerant.

                        Although I haven't been able to reproduce some of the numbers that Grif posts on his website, I think that from a practical standpoint the unit does what he says it will, which is to keep the car comfortable in ambient temperatures up to and exceeding 110 degrees F. In those conditions, the oil temperature runs in the range of 205-215 degrees F, at the upper range of normal. I have found that when using the air conditioning, the oil tempearature runs in the range i gave, almost independent of outside air temperature. I think that this is because, at least in part, as the temperature increases less heat comes out of the rear deck lid condenser and the other condensers become more important. The only thing I would do differently if I were to do it again would be to get the continously variable evaporator fan control, but it's not a big deal. The original Behr knee pad is perfectly adequate. I have found that factory support from Griffiths is excellent.

                        The only quibble I have is with Grif's claim ihat the stock alternator is adequate. I was skeptical of that and probably would not have proceeded if a high output alternator was not available (95A from Pelican Parts, no longer offered). Depending on evaporator fan and temperature settings, the ac system draws up to 33 A. The stock 50A alternator in the early cars will only generate about 10 A at engine idle speeds, so discharge rate from the battery when stopped at a light can get to be quite high, and the stock alternator lacks sufficient reserve capacity to recharge the battery during the short distance to the next stop. A high capacity alternator is available now from an outfit with a website classicretrofit.com. I have no experience with their product but it looks like it would be at least as good as the alternator I got from Pelican Parts.

                        Solving this electrical problem turned out to be more difficult than just replacing the alternator, although that is a necessary part of the solution. However, I managed to do so and no longer get home and find that the battery lacks enough charge to restart the car to drive it into the garage. If anyone is interested I can discuss this problem and the approach to solving it in detail.

                        Comment


                        • #13
                          I saw somewhere that Vintage Air is working on a 911 setup. They are located in San Antonio, (Chisenhall family), and are real A/C experts. By the way they have evaluated electric compressors and have a good analysis in their tech section.
                          Frank's writeup above is probably everything you need to know to do a nice setup.
                          I am not a fan of 4 condensers, two well placed ones are enough to keep you cool.
                          My dealer installed unit was really inadequate. The big changes were the front condenser in the RS front spoiler, and the ducktail which pushes more air into the engine mounted condenser. The VWP vents are bigger than the Behr vents. I also believe that the upright evaporator in the VWP unit is more efficient and easier to keep clean than the horizontal evaporator hidden away.
                          I also second Frank, R12 is the only way to go on air cooled cars.
                          The only thing I have been thinking about is to change my front condenser in the spoiler to a larger more modern unit.
                          I also have the 85 amp Valeo alternator.
                          flatsixer
                          aka rstarga
                          Last edited by flatsixer; 09-24-2022, 01:40 PM.

                          Comment


                          • #14
                            Agreed David; 4 condensers is like having 4 wives. (2 is enough!)
                            Easy rule: The more connections and fittings, the more likely one will eventually encounter leaks.

                            Griffith’s…
                            Their published temps are nothing to write home about. We beat them every time. Even in 110 degree ambient weather in Phoenix.
                            #r12rules
                            Old, white cisgender male oppressor.
                            Influencer/Life Coach.

                            www.beckseuropean.com

                            Comment


                            • #15
                              Originally posted by Frank Beck View Post
                              Agreed David; 4 condensers is like having 4 wives. (2 is enough!)
                              Easy rule: The more connections and fittings, the more likely one will eventually encounter leaks.

                              Griffith’s…
                              Their published temps are nothing to write home about. We beat them every time. Even in 110 degree ambient weather in Phoenix.
                              #r12rules
                              just out of curiosity, what vent temps are you seeing in the cars utilizing your setup?

                              Comment

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