Electric ventilator for radiator - questions

[Belgian1979]

I have been busy mounting a pair of Electric 11" fans with shroud to my radiator. It's the fan combo similar to the one in this link ( the black dual fans in the small pictures - you can click on them) :

http://www.dewitts.com/collections/corv ... radiator-1

These deliver 1400 cfm per fan, so 2800 cfm in total. Would that be sufficient in place of the factory engine driven fan ?

As you can see the fan is not as wide as the radiator core. Due to interference with the A-arms I had to move the shroud over to the cold side of the radiator this leaves about 2.5" of non covered area on the hot side. I was thinking of solving this by making an alu cover that goes from the shroud to the radiator tank on the side and drilling some holes in the side of the plastic shroud so the fan would be able to draw hot air from that area. Would this help/work ?

[looper]

Hi Belgian,
Can't answer your question about if it's enough air volume (200hp engines make a lot less heat that 800hp engines), and I don't know what you have.
Electric fans don't seem to do as well as mechanical fans, so BIGGER is always better.

When installing radiators, make sure all your original air dams are installed in front of the radiator and a full shroud behind. Think funnel into radiator and funnel out of radiator. No flat panels, they will block air flow. Consider how the air would flow throw the radiator if you removed the fans, would the shroud restrict air. Many aftermarket shrouds do. Had a customer who's engine would run cooler down the highway with the aftermarket shroud removed.

I realize this is not always possible in every application.

[lada ok]

You shouldn't need fans at all once your up and moving, there only really there for city work, idling or maybe hauling a big load up a cliff face !

[user-23911]

That's right, work out the maths on it and your electric fans might give an equivalent of 15MPH forwards speed.
So long as you don't get stuck in a traffic jam, you don't need them.
At the same time, once you're faster than 15 MPH, they actually hinder airflow.

[wyrmrider]

Would that be sufficient in place of the factory engine driven fan ?
sufficient maybe
equivalent- not as good as a 7 blade 3" pitch or 2 1/2 "pitch 9 blade mechanical fan on a HD fan clutch (9 blade is much quieter)
Ford Crown Vic- Lincoln big electric fan works almost as well on cars-- can be a problem towing or trucks
take a lot of juice- but less hp than mech fan
use good size wires and good relays

[Belgian1979]

As for airflow, they have rubber flaps on top and at the bottom to relieve any pressure.

What kind of tests do I need/can I (to) perform to assess their suitability ?
I agree that the mechanical fans move more air and are more robust. However, the factory shroud takes a lot of place and exactly the place I need to get a cold air intake in the car. I have been having my doubts about using high rpm with them (even though they have the fluid coupling)
I do have one drawback and that is that on a C3 the radiator is tilted backwards and that makes it draw less air. The radiator needs to be sealed of as good as possible which makes for a balancing act as my cold air intake is going to be drawing air over the radiator and radiator support, so I need to leave the area above the radiator unsealed.

As for switching the fans on : I have the temperature sensor in the head and the ecu handles the switching of the fans. It has an on setting with an hysterisis. For example : on at 210°F with an 10°F hysterisis switches it off again at 200°F. Thermostat is 195°F unit.

Thanks for the input !

[PackardV8]

At the same time, once you're faster than 15 MPH, they actually hinder airflow.

You shouldn't need fans at all once your up and moving, there only really there for city work, idling or maybe hauling a big load up a cliff face !

I'd put those statements in the "Yes, No, Maybe" area.

I've had builds which ran hotter at highway cruise without a fan. In those cases, the fan helped create a lower pressure area behind the radiator which increased air flow. Your opinions and results may vary, but mine are from personal experience.

[Belgian1979]

I put them to work today when mounted to the radiator. They are putting out a healthy amount of air. I can feel the cold air rushing into the radiator from the other side as well. Not sure if that would suffice though. Lots of comments on the vette related forums that these should work.

[lada ok]

At the same time, once you're faster than 15 MPH, they actually hinder airflow.

You shouldn't need fans at all once your up and moving, there only really there for city work, idling or maybe hauling a big load up a cliff face !

I'd put those statements in the "Yes, No, Maybe" area.

I've had builds which ran hotter at highway cruise without a fan. In those cases, the fan helped create a lower pressure area behind the radiator which increased air flow. Your opinions and results may vary, but mine are from personal experience.

I would consider that result to be a poor radiator combo and not a fan issue... although, the fans did infact help
I once had an issue with a customer car, around town the thing ran at normal temp, I could hear the cooling fan click in, out in the highway, the temp was fine, but sometimes the car would suddenly start to over heat, with one of these episodes, I managed to pull over, pop the bonnet, and yes, the elec fan was going ok then to my horror I realised the hot air wasn't blowing onto my hand .... some previous idiot had wired the fan back to front it was blowing and not sucking, therefore stopping the air flow through the radiator

[user-23911]

If you put it on a manual switch you can monitor the temp keeping it off.
That way you'll know what's going on.
I had a Toyota hilux with a 2LT in it for a while. I left the electric cooling fan disconnected because it sucked too much power.
It never overheated on me and that included all the times I had the car trailer on the back with the play car on it.
Then the play car, I've got that fan on manual too (aircon switch), only because it's running the wrong computer.
I don't get stuck in traffic though.

[wyrmrider]

be sue and blug all the unneeded holes in the radiator support, and to hood
dbl check the air dam under the radiator- creates low pressure behind- higher pressure in front
every little bit helps
water pump with a plate on the impeller helps
also if you can shut off the thermostat bypass- that really helps
If interested I can post up some clues/ kludges

[Belgian1979]

Yes, please do.

I just received a wiring scheme with 3 relays that allows me to run the fans at low speed and at high speed. Might be a good thing to have some airflow through the thing from say 140°F onwards at low speed and have the high speed turn on at above 200°F.

Meanwhile I have tested the fans in the car and they seem to pull a lot of air. I can feel the air rushing in from the front. I have also used a selfmade alu shielding so that I can suck the air from the non covered area. Just need to seal it off on the side to the radiator. Will use a cut up piece of rubber for that.

[wyrmrider]

It is important to have van flow in stop and go traffic if you have AC- it makes the AC works much better even if engine temp is ok
I have a relay to turn on pusher fan when AC off then another that shuts fans of at around 28 MPH
73 Chrysler 400's had a nifty switch that fit between the spedo cable and the trans that controlled the Vac Advance (no low speed Vac Advance) which works for older mopars including my dakota, others can hook into Speed Control lower limit or whatever

Bypass only needs to be plugged when cooling system is under capacity
anyone who has had to turn the heater on pulling a steep grade in the summer time if stop and go traffic due to some accident knows what I mean
answer is to get a "Desert Cooler" core for the radiator

On BBM we used to run the HD Truck thermostat housing which had a bypass closing thermostat- Robershaw so good luck with that one- besides it was heavey
Some foreign cars- some Mercedes have a separate thermostat casting (box) with hose in and out- I think for clearance or space issues- these are easy to plumb into upper radiator hose system, plugging the stock bypass - they also use a special thermostat with a second disc to close off the bypass when the thermostat opens

In a tow vehicle you can rig a heater hose valve with a pull cable- leave it open all the time except in those very hot situations
ON sbc and others can be used in conjunction with the extra cooling hose systems- still have to plug the stock bypass hole

any other ideas appreciated
here in sunny southern california we have several tough situations
I -5 Grapevine
I-15 San Bernadino to vegas 3 really long hard pulls
Road from I 10 near Palm Springs to 29 Palms
Highway 66 Desert and Colorado River to Flagstaff
and other Rocky Mountain passes
Breaknet Pass ovr the Great divide- trucking on down the other side
etc

[Belgian1979]

I have run without bypass in the block before. This was with the stewart thermostat with bypass holes. The engine warmed up way to slow and didn't come up to temp when outside temps were low. I now have a bypass line from under the thermostat to the top of the waterpump for this reason. No overheating issues so far, but this was still with the factory fan.

I was trying out some setups with tubes to get cold air to the engine from the front of the car which is a mayor pita. I can get over the radiator support with some flattened hose but then I'm struggling with the hood going towards the inners of the car in the front of the C3. When going around the hood in open position the tubes (2X 3.5") are in front of the radiator obstructing airflow.

[jsgarage]

If the rig is already mounted and is sucking, not blowing, your next move might be to make 100% sure the fan motor is getting a full 13.2VDC. Electric motor power- and the airflow delivered- is NOT proportional to the voltage. For instance, reduce delivered voltage to 11.5 volts due to sloppy connections and you might lose 40% of your airflow. Small hand-held anemometers are ridiculously cheap these days- I bought one from a Chinese supplier whose name I cannot even spell, let alone pronounce, and it came in very handy in comparing electric fans for radiators. I don't much care for exact numbers here- only for comparisons between assemblies. Works for checking air volumes in A/C ducts too.