What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

Electric fans?

Put a 240* temp switch in the cold side of the tank and you'll have some serious problems way before the fans kick on. Just using that 240* switch as an example, there are plenty that work at much lower temps I'm sure, just had to mention it though.

Curious why you say it's better on the cool side? I'm sure if you knew the correlation between inlet and outlet temperatures you could use that method, but if you don't know the temp in the heads or intake with the corresponding radiator temp, I don't see how you could know what temp the fans should turn on to prevent overheating in the hottest portions of the engine. Fan's can't cool the radiator below ambient (not even close in use) obviously, but they theoretically can cool it well below engine operating temp.

It's a closed system, so raised temps in one location will reflect everywhere, but 200* on the cool side of the radiator could be 250* at the heads.

I would think it much easier (cheaper) for GM to run a temp probe in the radiator than the intake, but thats how they did it for all vehicles I am aware of...they must have had a reason to do it that way, no?

Pretty sure most of the aftermarket setups take the temp from the radiator, but the only reason I see for that is simplicity...they don't have to worry about fittings between makes and years.

I'm going to have to agree with the airflow statement, the electric fans probably don't impede airflow while turning anymore than when shut off, (because they will "freewheel" if the air pushing on them is greater than the speed they are pulling air in) but running all the time induces more load on the alternator when not required, and if not on some sort of switch, as was mentioned, that can be detrimental to fan and radiator life in water. /forums/images/graemlins/smile.gif
 
Do you have both fans running? I only have the left one hooked up right now. I didn't come on at all. Until I jumped acrossed the relay. Had an ammeter on the wire, it spiked at 47 amps, then settled down to about 14.5 once the fan was running.
 
I used two out of a mini van(15.00 at junk yard) then ran a relay single 30 amp adjustable relay(30.00) that i got from advanced auto parts.
I put my sonsor/probe on the cold side and my needle doesent move it keaps it right on no matter what i am doing
I also ran a switch for manual use for deep water crossing(nice option) /forums/images/graemlins/grin.gif
 
[ QUOTE ]
Curious why you say it's better on the cool side?

[/ QUOTE ]

I'm with you on this one m j.

It makes most sense to put the switch in the cold side of the radiator because if the coolant is already cool enough when it leaves the radiator to enter the engine, you don't need the fans.

An increase in temperature of the cold side of the radiator would tell the fans right away that they are needed.

It makes no difference what is coming out of the top of the engine, that is supposed to be hot. If the cold side isn't cold enough, the radiator needs more airflow.
 
[ QUOTE ]
It makes no difference what is coming out of the top of the engine, that is supposed to be hot. If the cold side isn't cold enough, the radiator needs more airflow.

[/ QUOTE ]

So how do you know what is cool enough to keep the engine from cooking? You'd have to be an engineer to know what temperatures the cylinder heads are seeing when the inlet coolant temp is XXX degrees.

For instance (made up numbers here) if the coolant inlet (to engine) temperature is 210*, how do you know it's not boiling at the cylinder heads, when inlet temperature of 200* would eliminate that boiling issue. (answer is, unless you have measured and studied the coolant temp at the heads, and the correlation between inlet temperature, you are just guessing)

You are working on keeping the *peak* coolant temperature from going beyond the boiling point of the coolant...if you don't know what cylinder head coolant temp is, you can't say what is cool enough going in to keep it form reaching the coolants boiling point.
 
think on it a bit more

the only thing that controls engine temp is the thermostat
it doesnt see "peak cylinder head temp" either

all the fan can do is supplemant the rad airflow, so why would you take the measurement from the head?
fan has no control over what happens in the engine but can assist the rad

if the cold side of the rad is ambient, and the heads over temperature, turning on the fan isnt gonna do much but needlessly draw more power

I would start with the cold side temp sender at thermostat temperature and see how that works but I really havent looked at what temp to turn fans on

PS on the new semi trucks the fans come on at about 210* engine temp
 
Because if the head temp, which is most likely hotter than the cool side of the radiator, will actually turn the fans on earlier, trying to cool the water down more, sooner, so that the water, will do it's job better, which is probably why my Camaro came from the factory with a 215 degree switch in the passenger side of the block.

I believe if you install the switch on the cool side of the rad, the fans will not turn on soon enough to give any adequate cooling.

WAIT !! i have an idea !!!


lets ask TIM, he knows everythinig !!! /forums/images/graemlins/doah.gif
 
This is off the subject slightly, but it looks like electric fans take up less space than the stock setup? Is that correct? I mean, it looks like the shroud and all that sits pretty tight against the radiator compared to the big factory shroud. I'm just going by pictures though.

To me, it's a plus to open up the engine compartment wherever possible to make stuff easier to see and get at...
 
again this thinking thing doesnt seem to be catching on

if you are travelling at 90 mph
and the cylinder head gets warm
do you really think having the electric fan come on is gonna do anything helpful?
it will throw some more load on the motor in the way of draw on the alternator

this is really basic stuff here
 
Had a big long reply written up, but that just made me think more. /forums/images/graemlins/smile.gif

You are right. No matter what the inlet temperature is (-30* for all we care) the temperature at the thermostat will STILL have to reach it's rated temp before coolant starts moving through the block.

Even if the rear cylinders are at 220* and you introduce -30* coolant, you will just serve to keep the thermostat closed longer, until the point at which the coolant at the rear of the cylinders is where it is going to be anyway, and the temperature at the thermostat reaches its rated temperature.

Only way to reduce the temperature at the rear cylinders (again a for-instance) is to lower the thermostat temp rating.

In the case of injection setups, I guess it is just easier to keep it the way GM did it, at the intake or heads. However, if you have a switch that will operate in colder ranges, then you could just as easily do it at the radiator. Increasing or decreasing the temperature there will only increase or decrease the amount and length of times the fans come on.

F-body temp turn-on in '88 is 230*, measured near the thermostat.
 
I saw the placement on import cars and tried to think of 'why?' they chose it
this is not something I dreamed up
 
Well, I havent made the conversion to my 88 yet but have been running the Winstar Fans on my 71 ElCamino for a few years now with great success.

As Sandman stated, they are a near perfect fit (you can see the installation on my 71 link) I have a temp switch in the block on the drivers side since I couldnt fit the switch in the intake manifold. The switch I use comes on at 205 and off at 195 (I run a 180 stat in my car) I have each fan wired thru a 50A relay but the both tie to the switch so they both turn on when engaged. I also have the relays wired to the AC so when the AC is on, the fans are on.

When driving on the freeway, the airflow is great enough the fans never turn on. If the air is on, the fans continued to run but do not seem to affect anything because they are not pulling air, they are kinda running under no-load. I might install a toggle to switch the fans off while on the freeway with the air but not sure its worth it.

I will be doing my Blazer this summer as I cant stand the load the current clutch fan places on the vehicle and the air is useless when in traffic because of lack of airflow over the condenser.
 
[ QUOTE ]

I will be doing my Blazer this summer as I cant stand the load the current clutch fan places on the vehicle and the air is useless when in traffic because of lack of airflow over the condenser.

[/ QUOTE ]

Working correctly a stock clutch fan puts VERY little load on the engine when not engaged, and from all accounts (still no hard numbers) the stock clutch fan pulls more air than pretty much any electric fan anyone has had experience with.

I have my doubts about how much air the fan moves over the radiator at idle speeds (which is a problem for you obviously) compared to a good electric fan setup, but in other cases, the electric fans aren't good for much other than cleaning up the front of the engine, and being able to cool an engine thats mounted transversely. Plenty of studies have shown that when the clutch is "unlocked" power drain is very slight.
 
The truck came with the factory tow package.
The clutch is pretty heavy duty. When accellerating from a stop, it sounds like a UPS truck coming down the street. Its very loud. When the clutch starts to disengage, you can really feel the power pick up. When its "loose" its not bad. I just dont like the drag upon initial accelleration. Its going to get worse as summer hits the desert here.

Even with the shroud, the airflow isnt enough to cool the AC at idle. Ill swap it out and see if it works as well as my 71 swap did. /forums/images/graemlins/ears.gif
 
You must log in or register to reply here.

Latest Posts

Top Bottom