How do modern cars regulate temperature so well?
It runs 190 most of the time, but when it's hot outside it climbs over 200 - 205....
That's without AC which I am definitely going to add AND a mild 318 build....couldn't imagine what it would do with AC and more hp (stroker planned in future)
Some days when the outside temperature is mild, 190 around town and 180 on the freeway. ...
It's all over the place.
All seals in place and good condition.
Jeff
I don't like my older cars to reach 200* That's just me......
200°F is
not hot. Neither is 205°F. My Contour electric fans are set to keep my Duster between 200°F and 210°F, and really that's lower than it needs to be.
Remember what the stock thermostat on these cars was? It's a 195° F. You think they ran everywhere at 200°F? They did not. And most of the factory gauges do not have actual temperatures on them, so they're no better than a new car. Probably less accurate too.
Even with only a 7 psi cap boiling should be around 230°F. With a 16psi cap like newer radiators run it's more like 250°F. So I wouldn't stress anything lower than 220°F. Some of that is about tuning, I'm not saying you'll run your best 1/4 mile at 220°F. But on the street? Not a problem if it stays there.
From what I can see in this discussion is no one addressed the fact that the older cars aren't actually "regulating" anything. Regulation requires some "smarts" being built into the system. Older cars "attempt" to do it with what they had. Water hits a certain temp, fan starts in order to stop the rise, or bring it down etc, meanwhile the temp is rising because, that ramp up has already begun and it's not easy to stop, eventually, it will happen, but then the water might cool too much and the cycle starts over. The problem with this is of course, the timing of it all. It's like a diabetic who take insulin right before eating instead of 15 minutes before. You have to try to match the curves and the older stuff just isn't up to the task.
Nowadays, temperature control is often done with a PID loop. The system uses a controller, which "knows" based on the current temps, and rates of change measured by the differneces in the current and last few measurements, how to predict when to start and stop the fan. Doing this, you get a far greater accuracy than a simple on/off that's activated on a general temp.
Exactly. And, they're all electric fans. No worrying about what CFM the fan is putting out at a given engine RPM, the fan spins at the RPM it's rated for which means even at idle electric fan can pump out its max rated CFM. With a mechanical fan the lowest CFM it moves is at idle, which is usually when the engine is hottest because there's no air flow but the fan. And when the engine rpms are up and your fan is pushing a ton of cfm and stealing all kinds of power- you don't need the fan at all because the air flow through the front of the car is plenty.
Still...............I want mine to run like modern.
Do I not have enough radiator? Fan?
Better controller?
All of the above?
Jeff
More fan.
I looked up your fans, they're rated for 2,700-2,799 cfm. Which is enough, but, not much extra. The Contour fans I run are rated for ~3,000 cfm on low speed, and will move ~5,000 cfm on the high speed. The vast majority of the time the low speed is all I need, but I have had the high speed kick on a few times when I was stuck in traffic with outside temps over 105°F. But my 340 is .060" over and 9.8:1 with ported iron heads and a Lunati 60404. Not crazy by any means not not exactly mild either.
And your controller, well I'm not too sure about it. I looked it up, but it wasn't super clear about how exactly you get to actually control the fans. How do you set the temperatures?
I use a Dakota Digital controller. I can program the on and off temperatures for both the high and low fan speeds. If I remember right the "on" temps can be set in 1° increments and the "off" temp in 2° increments. It also has a 0-5 min run time on shut down that can be programmed, so just like a new car the fans will keep running after you shut the car down. It has a low voltage protection on that as well so it'll shut the fans down before it kills the battery if that's an issue. I've been using the one I have for over 6 years now without any issues, it runs the fans off of a pair of relays.
A better controller makes it easier to maintain the temperatures you want as long as you have the fan to do it. Based on your current temperatures you're fine, so a better controller might improve that some. Add a bunch of power and you might also want more fan though.
