Fan Switch and run-on

I've searched, but probably putting in the wrong criteria. Two questions:

1/ What limits do people have on their rad sensor for their fans? i.e. switch on/off

2/ Do you have any form of run on? If so how have people got this to work? I have a Dvies Craig controller, but not one fo the new ones, so the elctric pump will run on, but the fans would have to be controlled another way.

Thanks

Brett

Brett,
Chuck and I are tackling that problem as we speak. I am using the Spal fan controller and it has a function that allows it to run on after shutdown. There also ia a relay that has a timer. It is on Chucks build site. He is busy with his 350 Mustang resto so may not have installed it yet. Chuck was concerned the fiberglass was getting too hot from the exhaust in close proximity. So he found the relays with up to 10 minute timer to run his small fans in the engine bay. Unless you have an electric water pump, running the radiator fan will do little to aid in cooling after shut down. You need to move the water as well. I have a water pump two front fans and the two small 5" fans in the engine bay to keep it cool. I will use the spal unit to run the radiator fan and water pump. It has a high and low limit which you set to whatever values you want. It also tuns the units on slowly and ramps up to 100%. It will allow the pump and fans to run after shutdown until the high limit is reached and then it will shut down. Since I want to run the 5" units also I am planning to use the relay timer for them. I think the spal unit may not run long enough. Am at work right now so I will send some pics and a little more explanation when I get home tonight(after 8PM).

Bill

If you have gone for fuel injection most ECUs will run the fans for you.

I am running carbs.

I have an electric Water Pump, Davies Craig, but am running their first version of the digital controller that doesn't have the integrated fan functionality.

So I have the ability to run the water pump after engine shutdown, but not the fans.

brettmcc said:

I am running carbs.

I have an electric Water Pump, Davies Craig, but am running their first version of the digital controller that doesn't have the integrated fan functionality.

So I have the ability to run the water pump after engine shutdown, but not the fans.

Click to expand...

Surely the output from the controler could be used to energise a relay
That way you could wire in the rad fans too

Ian

IanAnderson said:

Surely the output from the controler could be used to energise a relay
That way you could wire in the rad fans too

Ian

Click to expand...

Ian,
I thought that, but then wouldn't it energise the fans everytime the pump ran? Probably need to look at the controller a bit more when I get home, but was hoping to try and get it installed this Saturday.

Brett

Brett,
You want your fan to run everytime your pump turns on. Yes there iis a long distance from the thermostat to the radiator, but it won't make a big difference cause it won't see the cool water til it gets back around to the thermostat. If I remember correctly, it turns them on slowly working up to full power as the temp rises. If your controller has manually set points of high and low you can set it to run on after shutdown. Wire it with the low point above the thermostat opening temp and the high point below the peak temp you want the water to be at. Wire a constant 12 volt line to the controller and to the relays with the controller controlling the coil line in the relay. Then it will run on til the high temp is reached and then shut everything down. If it isn't clear, email me and I will walk you through it. I think I have the Davies unit at home sop I will look at the manual to make sure.

Bill

Brett, does your controller just have 'engine run cooler/engine run hotter' adjustment?

Could the fans not still be controlled from a fan switch in the rad, fed with a source from the waterpump controller. So fans are switched as per a 'normal car' via switch located in rad (or fancy fan controller) but the switches are supplied from a source under the control of the EWP controller.

Or ave i missed something? Hope we find the answer coz i think i need it too!!

just looked out the instructions that came with my EWP and controller. it mentions an optional turbo timer for run-on configurations....

i suppose you could wire the the controller to run-on after ignition switch off but you would need a timer else the pump runs till lower thresold is met which has the potential to flaten the battery in extreme situations? Not looked yet but there must be some sort of timer circuit/relay available from RS/Maplin/CPC that could be used to provided a timed feed after ignition shutoff supplying both pump and fan control circuits.

Or is that over complicating things?? (i am still hanging the doors and getting bored so thinking about other things is fun)

Brett

How about a second relay in the circuit that will become acive only when ignition is turned off

Ian

Firstly Thanks to Bill for the information he sent.

Maybe I am overthinking this... but I like to worry, it turned me grey in my 20s

Maybe all I need is to wire the fans in a way that they will come on whwnever. Something like this:



I currently have a Revotec controller sitting in my box of bits that will allow to manually adjust. Or would people think a fixed temp unit, the 2 options CBS provide for M22 fittings are a 88/79 or a 95/86, switch on/off.

That was my thoughts in pictures and this combined with EWP/controller would allow run-on. Now with a static fan switch there is the possibility that the fan would shutoff too soon in run-on so pumping water through but no air movement through the rad to cool it sufficiently.

Is there a problem with running the fans constant whilst water pump is running? or maybe they could only run constant in a run-on scenario and be variable whilst engine is running?

Ant,
If you get one of the new DC controllers, 8030, then it has both pump and fan control. The problem I have is that I have the 8020, an earlier version that only controls the pump.

Brett

seems i have the older type as well...there has to come a break point where mucking around trying to do want you want with the bits you have is false economy and buying the right bit for the job is the cleaner/easier solution.

can always recover a bit of teh cost by putting old one back on fleabay

You guys haven't read your literature very well. The 8020 will run on after turn off, IF the water temp is above your high temp setting at turn off. If it is, the fan AND pump will run on for either 2 minutes or until the temp goes below the high setting. Which ever comes first.
http://http://www.daviescraig.com.a...L_CONTROLLER_12V___PART_No__8020-details.aspx
You need to look at your wiring diagrams.
http://http://www.daviescraig.com.au/Images/EWP%20&%20FAN%20DIGITAL%20CONTROLLER%20INSTRUCTION%208020.pdf
If you no longer have them they can be found on line. The 8020 came out with the lower flow rate pump(80 gpm i think). The 8030 is for the 115 gpm pump. Both will run on.

Bill

Bill,
My 8020 does not have the fan relay, its just called a "EWP Digital Controller", the instructions are different. Maybe the US version was different to the UK. My 8020 was for the 110L pump.

I'll check the wires when I get home tonight to see if there is an extra wire and also a fan LED.

Brett

Brett,
Check this out I stumbled on it looking for the wiring diagram. It is for the 110 pump or the booster pump. It alows you to use a thermal switch and run on.also.

http://https://www.daviescraig.com.au/Images/EWP110 24v 07-12-07.pdf

There are about three ways you can wire it and get run on. One that I am using is to remove the thermostat and wire it to run all the time. the warm up takes a little longer, but it will get there. It also lets you pick a little lower temp for the high setting allowing you to get a little more power out of the engine. The sacrifice is the less efficienbt runing engine. If you run it very cool, you may have to reset the fuel ratio or fuel maps(FI).

Bill

How are you going to switch the fans on and off when the car is running?

All you need to do is wire this up to a permanent live feed. So when the ignition is switched off the fans will still run until the water temp is below the high temp setting. The water pump will circulate the water to prevent hot soak. You shouldn't need any type of controller, the only problem with doing this is that theoretically the fans could run until the battery goes dead.

I have been running a 55 GPM electric pump now for 8k miles with a time off relay so the pump and fans are active for 2 minutes after shut down so it takes the heat soak out of the engine compartment. I also run a PWM (pulse width modulator) control for the electric fan in another car I have, it also uses Electromotive TEC2 EFI control. One problem I have experienced is the electronic fan control switch's the ground in order to control the fan speed, on electromotive product it seems to have an effect (induces a signal) internally on the EFI and DIS control. So when the fan came on the engine would start running crazy and then just shut down, soon as the fan went off it ran perfect. Being a electronic tech this really got my head spinning but soon as I ran separate wires to the battery terminal for power and ground the problem when away. I am not meaning to ramble but beware that these PWM type devices do cause induction of signals strong enough to cause problems. So if you experience such problems I would check the controller first. As far as wiring of relay and pumps I would be happy to draw you out a diagram if that would help.

Jon,
"How are you going to switch the fans on and off when the car is running?"
Here is a reference document to refer to.
Cooling Fans
All you need to do, if you are using a controller is to wire the relay coil wire( 86 ) to the fans into the same circuit that turns the pump on. It will run at the same time as the pump. Since DC uses an on off scenario the fans will also. For run on you also will need a fused continuous hot wire to the fan relay(87). The coil wire will control the on off of the fan and it will turn off at the same time as the pump.

Jack,
You are running your pump and fan for 2 minutes after shut down. My question is, is 2 minutes long enough? If using a manual input temp signal to turn the pump off(Spal unit), what is a good setting??? For that matter, what is a good "on" value???

Bill