Gojira94
Newbie
Any reason why the want for a PWM controller? Me personally when the engine hits a certain temperature I don't want it going past that at all.
How it works is the fans comes on with soft start at the threshold temp you set on the controller. They then ramp up/down as far as needed to maintain that temperature. Since it monitors coolant temp coming OUT of the radiator, that's going to be cooler than the coolant temp in the block/ heads. The dash temp gauge reads the sensor in the head. The ECM reads the one next to the water neck where coolant goes TO the radiator, coming straight off the heads (for a Gen I SBC), where it's as hot as it gets. You just dial the fan controller down to where the temp read at the ECM's temp sensor is where you want it. This requires that you find a way to read ECM/PCM temp signal from the sensor while calibrating the controller using whatever logging tool you choose. I use the EBL's WUD.
I'm running a 180* thermostat. My typical running temps are 174-182* since my cooling system is pretty much all new and pretty darned efficient. On cold startup, the fans will be off or at idle % until the thermostat opens and sends hot coolant into the radiator. This helps the engine get to operating temperature faster and reduces emissions by getting the coolant temp-based closed loop qualifiers met sooner. After shutdown, the temp would otherwise go up to maybe 190-195+ on a really hot day with the removal of circulation in the cooling system. The only downside to this setup is it's not 12V ignition controlled via a separate relay so it runs after engine shutdown like my Accord lol. Granted, all it's doing at that point is cooling what's in the radiator and does nothing for the coolant in the block and heads but the engine gets a shot of cooler water on restart within 20-30 minutes or so.
With a dual battery setup you could run an electric water pump and relay it to the fan controller and have the water pump and fans cool the entire system for probably 3-5 minutes after shutdown. Practical? probably not. Possible? Hell yeah.
I plan on setting it to maintain 168-172* by the water neck/ECM temp read (just a tad on the cool side to maintain timing/ avoid detonation issues at 10.2:1 compression).