Quote:
Originally Posted by dontlifttoshift
We just did a Dominator in a 32 and we used a holley 500 PSI pressure transducer. This allowed us to skip the binary switch and the gm pressure sensor and do it with one sensor. We control the pwm fan and control compressor clutch engagement (high and low pressure cut off) through the ecm.
So far, it works. (End quote)
Originally I posted this under another topic, but thought it might fit better here.
I have a HP, not a Dominator, so maybe this won't work for me, also I am new at this so forgive me if I ask dumb questions. I have been pondering your solution and trying to figure out how you did this. I assume the 500PSI transducer is somehow plugged into the A/C line, presumably on the high side. The output from that transducer must somehow get into the ECU, (Inputs?), and set up to protect the A/C system in the event of too high or too low system pressure. Then is there a set point to turn on the fan, or speed it up, when the pressure reaches a particular threshold? Then is the cooling fan controlled by the ECU through a PWM for regular (or non-air conditioned) operation? If this is the set up, it would seem that some relays or diodes be necessary to prevent back feed of electricity.
Any assistance you can offer will be greatly appreciated.
Thanks, Larry
As an addendum, my '57 Chevy uses two Spal fans wired in both series and parallel, controlled by two temperature switches of different temperature values. At the lower temperature the fans come on wired in series, so they run at approximately alt speed. When the higher temperature is reached the fans which over to parallel wiring, therefore running at full speed. The trinary switch will override any operation or no operation of the fans and go to full RPM for the duration of what is commanded by the trinary switch. This system works well, but I do like the idea of a system that will keep the engine operating temperature more stable on a reduction of fan operation that is offered by using PWM. My Studebaker is still in the build up phase so it would not be that difficult to set it up with a PWM.
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