When to turn on and off cooling fans?
I have an CTS-V LSA engine in my 67 Camaro. I'm using Entropy's radiator which has two 12" radiator fans. In front of the radiator I have the C&R heat exchanger for the supercharger and Vintage Air condenser in front of that. I recently add two Spal 6.5" pusher fans in front of the condenser. All four of the fans are controlled by a BCM that I designed myself. This BCM also has inputs for a radiator mounted temp sensor and A/C trinary switch. The two radiator fans are PWM controlled so I can command whatever speed I want for them and the two pusher fans are just on or off. What I'm trying to figure out is what temps I should be using to turn these fans on and off.
Right now when I'm at highway speeds the engine temp is always right around 195* which is the same as the thermostat that I am using. In normal stop and go traffic the temp will rise to around 210*. But if I get caught in really bad traffic where I am forced to sit in one place for 15 minutes or more the temp starts to slowly creep up to 230* and even higher if I have to wait longer. Keep in mind this is in Dallas area where the outside temp is already 100*.
So what are normal engine temps for this engine and at what temp should I start to freak out? I used to freak out when it started to get into the 230* range but now I'm thinking that might be normal. The other question is what temp should I start the radiator fans and at what speed? Right now I command them both to come on at 180* at 40% then at 195* at 75% and finally full on at 200*. If the trinary switch is on then both fans are commanded on at 85% unless the engine temp is 200* or more in which case the fans will again be full on. The two pusher fans are on whenever the radiator fans are on, but I'm already thinking about changing this to just having the pusher fans on only when the trinary switch is active or the engine temp is above 205*. I'm also starting to think that I have the radiator fans coming on too early. What are your thoughts?