D1SCTransAm

Long detailed response below!

Thank you for the helpful insight! The fan controller definitely works. I spent a lot more time looking into this instead of responding without context.

The temperature probe supplied by the Davies unit is my main focus now. With your info, I tore into the CSR pump wiring first and I can confirm the original owner may have lurked these sites as he installed the stand-alone relay properly.

Relay Wiring:
BLK-grounded to radiator core (I wizzed the metal and took the time to professionally redo 3 grounds sharing this point)
YLW-found this wired to the A/C fuse instead of fuse#11-Ignition (both only stayed hot at Start/EOR)
RED-Wired to positive multi-trunk on passenger side

Pump Wires:
Black was grounded at pump relay as normal
Was it Orange(?) for pump power

I stated earlier I painstakingly disassembled the 2 garbage fan controllers completely from the engine bay and installed the Davies dual unit, to the letter per instructions. I set the unit to 82* C (179.6) and at that time, the probe was in the upper section of the radiator. Here's where the fun starts. I mentioned with my infrared temp gun, every spot I would target would range from low 130* to around *180 (this includes radiator upper hose (cool return(?), lower hose, upper hose before thermostat housing, thermostat housing, pump, pump housing. The last 4 ALWAYS are hotter than other targets of course.

Before I did the thermostat and found the original owner installed a standard Chevrolet V8 Tstat, there was a 30* difference from the actual upper hose at the water neck and the thermostat housing itself, even though they were inches apart. That issue is no longer.

So I feel the temp probe is the "culprit." My radiator is a big case dual core aluminum unit amd that beast doesn't get hot unless it's hot out. If the probe is only reading say...137* from the fins but the PCM is seeing 200* in the housing via the ECT sensor, the controller is lagging far behind, allowing the internal coolant temperature to reach "unsafe" levels. I data logged again on Sunday and same thing, I was able to watch the ECT temps rise to 195* just before home. I then targeted all the same areas with the gun and again, fan controller probe when I shot it showed 152*. Once the engine was off for a couple mins, the probe hit 180* and the fan came on once and the temperature never went over 178* again.

Injuneer

I really can’t comment on the Davis controller, the probe, or the whole setup. Just too far removed from the factory system which is very reliable. I don’t understand why people feel the need to trash it.

I ran the stock PCM/relay fan controls (Fan1/Fan2), reprogrammed fan on/off temps. My max fan2 on temp was 192°F, based on the dyno tuning on an engine dyno. Only non-stock components were a Hypertech 160° ‘stat and a Griffin aluminum radiator. Never had a problem of any kind with coolant temperatures, and that included ~800 HP nitrous assisted pulls on a chassis dyno. Street and strip use never showed any issues. I did not have A/C, so no condenser to block the radiator. The Griffin had the stock oil cooler connections, cooler was retained, Had a stand alone fan assisted trans fluid cooler, because when I bought the Griffin I was still running the T56, so no trans cooler. When we went to the TH400 it needed a cooler.

I had dash/pillar mounted gauges for engine oil and trans fluid temps, and monitored the PCM coolant temp reading with a Scanmaster LT1 digital readout.

https://www.camaroz28.com/g/picture/28411029

https://www.camaroz28.com/g/picture/30343406

https://www.camaroz28.com/g/picture/8152781