JFC Posted March 31, 2025 Posted March 31, 2025 Hi! I own a carrera 3.2 from 1986 fitted with the single condenser version of the AC. In hot days (hot...not eaven the worst summer days) it does not do the job....it still gets hot inside. I am from argentina we have lots of 30+ degree days.... I just got the car...i reviewed the way the AC is installed and it seems to be just like your manuals say. How can i be certain the AC is working propperly? Can I add the second condenser to my current system? will that make the air colder? thanks Juan Quote
classicretrofit Posted April 1, 2025 Posted April 1, 2025 Good morning. We would advise having the system re-gassed by an air conditioning service centre. Systems can lose pressure over time. A second condenser will greatly improve performance. Quote
Greg Posted July 8, 2025 Posted July 8, 2025 I have a customer that had another shop install your Classic Retrofit ElectroCooler system and they got the system to work but the cooling performance is poor at best. The system is installed in and original 1988 911 Safari car and necessitated a rear condenser install behind the left rear tire with basically no air flow. I have been told they also installed your high output alternator but I have not verified this. The customer has reported to me he invested $17,000 in parts and labor and over a year trying to get AC working properly. I have only been able to get the center vent temperature down to 65 degrees today with an ambient temp of 95 degrees. I had to drive the car 15 to 20 minutes in order to get the vent temperature down to this point. The vehicle is located in Reno, NV and it is going to get a lot hotter and dryer. We will be in triple digits with 7% humidity next week and we are at 5000’ of elevation (no air to cool with). I have been reading your instructions and will need to connect to the system and see what the settings are and if they are set correctly (probably not). I will also test the pressure reading and confirm they are within specifications. Assuming the charge is correct and some settings are wrong with regard to alternator size, what else should I be checking? Here are the main issues I think I will have to address in order to get this system to the same level of a engine run system: 1. Add another condenser, probably two 2. Get flesh air ducted to the condensers to cool them down vs. hot engine air that is doing nothing for us. 3. Install another battery and/swap to LifeP04 larger batteries so I can run the compressor a lot more at idle I have a great pair of 1600 cranking amp lithium ion batteries I can steel out of his other car that will fit in the stock battery location. In theory this would quadruple the battery amps and the base voltage would be higher. 4. Add another alternator to the engine and ensure I always have enough power to run the compressor 100% Recommendations or thoughts are very welcome. I have lots experience with standard engine driven systems. Thanks, Greg Quote
Jonny Retrofit Posted July 23, 2025 Posted July 23, 2025 Hi Greg, Sorry to hear of the struggles, I agree with most of your points. Points 1 and 2. For hot climates two condensers is recommended and they should be installed away from heat sources - e.g. at the front of the car. Anything blocking free air flow will greatly affect performance. Point 3. Yes to LIfePO4 battery since the voltage won't sag as much. Assuming it is the 3.2 Carrera engine then the pulley ratio should be ok but increasing the idle will also help. In the ECU, you can lower the low and moderate battery thresholds so the compressor will hold high speed for longer. Point 4. Our 175A high output alternator will produce around 70A at idle speed but over 100A at 2,500 RPM which is ample. The system as shipped is set to use max 75A. This can be increased by changing ECU settings but care must be taken to have very good connections and grounds to avoid cable heating. And some more: If the car has heat, make sure it is switching off completely or it will bleed hot air into the AC system. Block the hood inlet completely to make the system 100% recirculation. Please do post the settings from the ECU here. Quote
Greg Posted August 6, 2025 Posted August 6, 2025 Classic Retrofit, The other shop did a pretty good job with the install but dropped the ball at the end. The cabin air temp sensor was wrapped in foil laying on the cold air supply tube to the dash vent right at the evaporator (reading way cold output air). The return air tube was disconnected from the air box as it was not routed per the instructions. Both these items are corrected and installed per the instructions. Car has dual condenser, both in the rear drivers side fender with an electric fan on each one. One is in front of the tire and the other is behind the tire. Customer contacted the shop to retrieve the USB cable and was informed that they never connect to the the controller. I updated the firmware and change the setting per the instructions to the following: (c) Classic Retrofit Ltd 2017 Electrocooler A/C ECU Settings: ======================================================================== Description Setting Value ------------------------------------------------------------------------ Firmware Version 1.17 Control Mode: Hi/Lo[0], Climate[1] MOD Climate[1] Compressor Drive Signal Sense [0-3] SIG PWM Hi, En Hi [0] Button Type: Mom[0], Lat[1], Blower[2] BUT Moment[0] Battery Low Voltage BLO 11.8 V Battery Moderate Voltage BMD 12.3 V Blower On Sense Voltage BLV < 7.0 V Compressor Target Current (max current) CTG 75.0 A Condenser fan on high threshold CFN 38.0 A Condenser fan off low threshold CFO 30.0 A Cabin Temperature Setpoint CTS 20.0 C Evap Temperature Cutout (freeze protect) ETC -2.0 C Max Time Below Good Voltage TBG 60 s Max Time Below Moderate Voltage TBM 120 s Compressor low speed [0-100] CLO 1 % Compressor high speed [0-100] CHI 55 % Controller Proportional Constant KP 8.00 Controller Integral Constant KI 0.01 Controller Derivative Constant KD 0.05 NTC Temperature Probe Constant KBET 3950 ------------------------------------------------------------------------ I think there is room to improve the settings a bit but there are other issues to resolve as well. I ran the car today in the morning 70 degrees and the afternoon when it was only 85 degrees F out. In the cold air the AC worked perfectly. In the 85 degree air it worked okay but needs more cooling, center vent was 45 degrees f. I can send you a recording of idle and test drive data for today's run. Here's what I am looking for: 1: Replace the inline fuse (80 amp) so I can run higher compressor speeds with the large alternator 2: How can I confirm if I have the 150 or 175 amp alternator? What is the difference with the idle amps available with each one? 3: Volt drops way to much with the oil cooler fan running and ruins the AC system, speed drops to 30% or lower. Better aftermarket/second oil cooler maybe the solution. 4: the Evap temp driving the car only got down to 9 or 10 degrees C, that seems high and maybe the system needs a recharge (I have not tested pressures yet). It was running 22.5-23.5 degrees C at the cabin sensor. 5: I need to install the two 1600 cranking amp LifeP04 batteries, total of 3200 cranking amps and allow the car to run off the batteries more at idle. Do you have recommendations for setting with these batteries. 6: Looking for any other ideas? This system is working better but it will not work in the 98 degrees to 104 degree days we should be having. 7: The airflow on the system seems low, is there a way to improve this? It's a gen 2 system. Cold air leaks around the end caps and sealing them would help a lot. I have a capped duct for the clock vent but the customer will not allow me to install that. I could fab a port and add it to the center vent. The radio has been deleted and I could fab a second center vent to that location. Any thoughts on those options? 8: Customer wants two more system for his 930's if we can get this working better. Thanks, Greg Quote
Jonny Retrofit Posted August 6, 2025 Posted August 6, 2025 Glad to hear things are improved! Set the CHI back to 95 1. You can increase the CTG amps to 85/90 (with higher fuse rating). Make sure all your red cabling and grounds are super solid. 2. All the alternators are 175A. the idle output is around 75A. 3 / 5. The voltage will 'sag' with a lead acid or AGM battery. Lithium should fix that. 4. As the cabin temp (read by the cabin sensor) approaches the setpoint (CTS which is 20 deg), the compressor will slow down, hence the evaporator temp will rise. Set the CTS a bit lower (say 18C) and the compressor will run a bit harder. It's a balance since you don't want the compressor to be running full speed all the time - too much on the charging system. TBH, a 45F centre vent is pretty good. That's just a few degrees above freezing and better than most factory systems. 6. These cars are leaky, they have no insulation or window tint like a modern car. There should be a foam gasket behind the hood inlet grille giving a 2/3 block of the hood air. You can completely block the hood inlet to make the system fully recirculating. You can pad/insulate the areas around the blower and ductwork. The easiest thing you can do is be sensible with the car. Don't leave it parked in direct sun to heat soak. Don't leave it idling to cool down. Open the windows and sun roof if the car gets heat soaked. Drive the car immediately so the system can run in high power mode (as the compressor backs of at idle). We are getting the best performance out of what is a very small pump but every system has its limit. On a 100F day, you should be comfortable within 5-10 mins of driving. 7. How have the side vents been ducted.? They should be connected to the small 40mm outlets. It's tempting for the installer to connect them to the larger 60mm ports (as they are the same size) but all this will do is make the centre vent output really poor. Do you have our underdash vents? They can help to distribute the air better. The clock vent is a huge benefit so I suggest you try it. Radio delete panel vent could work but you'd have to make a hole in the car! Quote
Greg Posted August 7, 2025 Posted August 7, 2025 Jonny, The side vets are ducted correctly to the 40mm ports. I did some more digging and found some more issues with the install. The battery ground strap was not replaced and I will upgrade that to a much larger cable to handle the increased amps when I swap in the LifePoe batteries. They had a battery disconnect installed that I know does not flow amps well and I removed that. Both battery cables were loose and would wiggle without much effort. I also found one end of the fuse connection for the AC system was sloppy loose after removing the heat shrink. I corrected all these issue and swapped out the fuse to a 125 amp. I then set the following parameters: CLO=10 CTS=18 CTG=100 CHI=95 I test drove the car but not in equal conditions, 83 degrees F out and cloud covered (so crazy for our weather). Plus the car was removed from the cold shop and not heat soaked outside like before. Center vent was running 40 degrees steady until the AC started to slow down to meat locker temperatures. I also found that sliding the top two levers both the right improved that air flow volume dramatically (rather than split for max center vent flow). The system is really starting to work well now. After my test drive I closed off the cowl vent to make the system 100% recirculation. I will get the car up on the rack and see if the engine ground has been upgraded as well, I am sure is has as the main power wiring from the alternator has been done. It's looking good for a real test on Monday with a 98 degree day forecasted. Thanks, Greg Quote
Greg Posted August 8, 2025 Posted August 8, 2025 Jonny, The AC system does not work once the car gets heat soaked. I left the car outside in the sun,, it was 87 degrees out and the temp was 120 degrees at the center vent. The fans for the condensers and AC compressor never turned on. I keyed (started) the car and off/on three time and the turned the AC on two plus time on each ket cycle. From what I am seeing in the data I got the USW switch is 0 , meaning it is not turning on the AC system. Please see data below and advise. Thanks, Greg V:14.4, I:0.0, S:18.0, C:34.0, E:35.5, D:95 V:14.4, I:0.0, S:18.0, C:34.0, E:35.6, D:95 V:14.1, I:0.0, S:18.0, C:34.0, E:35.6, D:95 V:13.4, I:0.0, S:18.0, C:34.0, E:35.6, D:95 *************************************** * ElectroCooler Firmware v1.17 * * (c)Classic Retrofit Ltd 2017 - 2019 * *************************************** V:13.2, I:0.0, S:18.0, C:33.8, E:35.4, D:0 V:14.4, I:0.0, S:18.0, C:34.0, E:35.4, D:95 DIAG:OK HiPower , BatteryGood , BlowerOn , BAT = 14.37 V , CompI = 0.00 A, BLO = 0.60 V , CEN = 1, SPD = 095, IGN = 1, USW = 0, CON = 1, FAN = 0, ACC = 0, D1 = 0, D2 = 0, D3 = 0, TC = 34.0, TE = 35.3, BT = 0, HiPower , BatteryGood , BlowerOn , BAT = 14.38 V , CompI = 0.00 A, BLO = 0.60 V , CEN = 1, SPD = 095, IGN = 1, USW = 0, CON = 1, FAN = 0, ACC = 0, D1 = 0, D2 = 0, D3 = 0, TC = 33.8, TE = 35.3, BT = 0, HiPower , BatteryGood , BlowerOn , BAT = 14.36 V , CompI = 0.00 A, BLO = 0.58 V , CEN = 1, SPD = 095, IGN = 1, USW = 0, CON = 1, FAN = 0, ACC = 0, D1 = 0, D2 = 0, D3 = 0, TC = 34.0, TE = 35.3, BT = 0, HiPower , BatteryGood , BlowerOn , BAT = 14.38 V , CompI = 0.00 A, BLO = 0.58 V , CEN = 1, SPD = 095, IGN = 1, USW = 0, CON = 1, FAN = 0, ACC = 0, D1 = 0, D2 = 0, D3 = 0, TC = 34.0, TE = 35.2, BT = 0, HiPower , BatteryGood , BlowerOn , BAT = 14.36 V , CompI = 0.00 A, BLO = 0.58 V , CEN = 1, SPD = 095, IGN = 1, USW = 0, CON = 1, FAN = 0, ACC = 0, D1 = 0, D2 = 0, D3 = 0, TC = 34.0, TE = 35.3, BT = 0, HiPower , BatteryGood , BlowerOn , BAT = 14.36 V , CompI = 0.00 A, BLO = 0.59 V , CEN = 1, SPD = 095, IGN = 1, USW = 0, CON = 1, FAN = 0, ACC = 0, D1 = 0, D2 = 0, D3 = 0, TC = 33.8, TE = 35.3, BT = 0, HiPower , BatteryGood , BlowerOn , BAT = 14.37 V , CompI = 0.00 A, BLO = 0.60 V , CEN = 1, SPD = 095, IGN = 1, USW = 0, CON = 1, FAN = 0, ACC = 0, D1 = 0, D2 = 0, D3 = 0, TC = 33.8, TE = 35.3, BT = 0, HiPower , BatteryGood , BlowerOn , BAT = 14.37 V , CompI = 0.00 A, BLO = 0.60 V , CEN = 1, SPD = 095, IGN = 1, USW = 0, CON = 1, FAN = 0, ACC = 0, D1 = 0, D2 = 0, D3 = 0, TC = 33.8, TE = 35.2, BT = 0, HiPower , BatteryGood , BlowerOn , BAT = 14.38 V , CompI = 0.00 A, BLO = 0.60 V , CEN = 1, SPD = 095, IGN = 1, USW = 0, CON = 1, FAN = 0, ACC = 0, D1 = 0, D2 = 0, D3 = 0, TC = 33.8, TE = 35.2, BT = 0, HiPower , BatteryGood , BlowerOn , BAT = 14.39 V , CompI = 0.00 A, BLO = 0.60 V , CEN = 1, SPD = 095, IGN = 1, USW = 0, CON = 1, FAN = 0, ACC = 0, D1 = 0, D2 = 0, D3 = 0, TC = 33.7, TE = 35.2, BT = 0, HiPower , BatteryGood , BlowerOn , BAT = 14.38 V , CompI = 0.00 A, BLO = 0.60 V , CEN = 1, SPD = 095, IGN = 1, USW = 0, CON = 1, FAN = 0, ACC = 0, D1 = 0, D2 = 0, D3 = 0, TC = 33.7, TE = 35.2, BT = 0, HiPower , BatteryGood , BlowerOn , BAT = 14.36 V , CompI = 0.00 A, BLO = 0.60 V , CEN = 1, SPD = 095, IGN = 1, USW = 0, CON = 1, FAN = 0, ACC = 0, D1 = 0, D2 = 0, D3 = 0, TC = 33.7, TE = 35.2, BT = 0, HiPower , BatteryGood , BlowerOn , BAT = 14.36 V , CompI = 0.00 A, BLO = 0.60 V , CEN = 1, SPD = 095, IGN = 1, USW = 0, CON = 1, FAN = 0, ACC = 0, D1 = 0, D2 = 0, D3 = 0, TC = 33.7, TE = 35.2, BT = 0, HiPower , BatteryGood , BlowerOn , BAT = 14.37 V , CompI = 0.00 A, BLO = 0.59 V , CEN = 1, SPD = 095, IGN = 1, USW = 0, CON = 1, FAN = 0, ACC = 0, D1 = 0, D2 = 0, D3 = 0, TC = 33.7, TE = 35.2, BT = 0, HiPower , BatteryGood , BlowerOn , BAT = 14.38 V , CompI = 0.00 A, BLO = 0.60 V , CEN = 1, SPD = 095, IGN = 1, USW = 0, CON = 1, FAN = 0, ACC = 0, D1 = 0, D2 = 0, D3 = 0, TC = 33.7, TE = 35.2, BT = 0, RUN:OKHiPower , BatteryGood , BlowerOn , BAT = 14.39 V , CompI = 0.00 A, BLO = 0.59 V , CEN = 1, SPD = 095, IGN = 1, USW = 0, CON = 0, FAN = 0, ACC = 0, D1 = 0, D2 = 0, D3 = 0, TC = 33.6, TE = 35.1, BT = 0, HiPower , BatteryGood , BlowerOn , BAT = 14.38 V , CompI = 0.00 A, BLO = 0.60 V , CEN = 1, SPD = 095, IGN = 1, USW = 0, CON = 0, FAN = 0, ACC = 0, D1 = 0, D2 = 0, D3 = 0, TC = 33.6, TE = 35.0, BT = 0, Quote
Jonny Retrofit Posted August 8, 2025 Posted August 8, 2025 Hi Greg, Since the User Switch is a momentary contact, it will only show USW=1 if the switch is held down. Anyhow... From your trace, the ECU has recognised the button press and gone into HiPower and is demanding 95% duty from the compressor. The problem is the compressor is not starting as the current (CompI) remains at 0. When the compressor does not start when demanded, it usually indicates a problem with the heavy power cabling. As you said before, there is a history of bad connections in the positive cabling and also the ground. I would thoroughly check these through, including the connection at the alternator. If connections have been loose, there is potential for them to get pitted/burnt and not make good contact. Quote
Greg Posted August 15, 2025 Posted August 15, 2025 Jonny, I am going over every single cable connection in the car to diagnose the issues. I removed the relay contactor and got the system working again when the car is cold (below 80 degrees). The system will not start above 100 degrees. I removed the alternator and found the stock OEM ground wire was used (10 ga maybe), not the large gauge wire sent with the alternator. I am sure this is the starting issue. What gauge wire do I need to run here? From you video online it looks like a 1 or 2 gauge wire is enough for the short distance. They made their own power cable and its 1/0 gauge or possibly a 2/0 gauge. I am sure the engine to chassis ground is OEM and way too small as well. Thanks, Greg Quote
Jonny Retrofit Posted August 18, 2025 Posted August 18, 2025 Hi Greg, yes that could be an issue. We use 25mm2 cable which is rated for 170A. You might also try lowering the CHI to 85. We have had some reports of 95 causing the pump to switch off. Quote
Greg Posted October 7, 2025 Posted October 7, 2025 Jonny, I was able to get the AC working great with all the electrical gremlins addressed and the LiPoe4 batteries installed. The Batteries really completed the install and the system is working great, but the outside heat has fallen off to much to be 100% sure, but we will see next summer. Do you have the kits to add the heat pump to our system yet? Thanks, Greg Quote
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