L31MaxExpress
I'm Awesome
With the 383, I am trying electric fans again. Making some changes from the prior setup though. This time around using a 34x19 radiator that completely covers the core support opening and 16" 3,000 cfm Flexalite fans. BP Engineering GMT800 fan harness and ac pressure transducer kit. Harness is installed and works well. Only need to lengthen the two control wires and route them to the PCM inside the engine harness. The PCM will be controlling the fans based off coolant temp and a/c pressure. I am adding a GM a/c pressure transducer to the a/c discharge hose between the compressor and condenser. I tested the fans on video. First on low speed with the motors in series for 6 volts each. Then on high speed with the fans in parallel and 12 volts each. Fans draw 9.25 amps on low and 37 amps on high. The startup amperage spike is also very low with this wiring arrangement. The PCM will also run the fans only as much as needed so less wasted energy. With the PCM controlling the fans I can adjust the idle airflow when the fans turn on and off to maintain a steady idle speed. The PCM is also going to control the alternator when I am done with the wiring changes which means stable voltage as the fans turn on and off. I am going to try to bend the trans cooler mounting bracket in toward the condenser to get more airflow through it. It sticks out close over 2" from the condenser now because the condenser is thinner. Even so the airflow through the trans cooler will still pull a paper towel against it on low speed and hold it in place. But with the 2,800 rpm stall converter its hard to go overkill on trans cooling. Picked up a parallel flow condenser with a lifetime warranty. With my discount at work it was under $80. The old style serpentine condenser (2 tubes snake all the way through it) was 2x the thickness and highly restrictive to airflow after nearly 25 years even though I had previously cleaned it and straightened the fins. The new parallel flow is thinner and being new and clean flows alot more air through it. Condenser design and function has been drastically improved in the 30 years since GM designed that early R134a condenser. The newer condensers typically reduce the a/c head pressure, let the a/c function better and help keep the engine cooler with the improved airflow.
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