Fan options

[chickenwing]

That bay is just sexy. More than 1 way to skin a cat! Looks like you had some space limitation issues also. Very nice work and thank-you for sharing.

[farside847]

Holly crappers! Man, that is a pic to save.

Originally Posted by bobs409

Has anyone read any test results of HP and MPG gains by going to electric?

[BobbyK]

Here's mine.
Two 14" Perma-Cool fans.Rated at approx. 2500cfm each.

I made the metal shroud.

The primary fan is controlled with a thermostat that's in the head.

The other I can manually turn on.
Both fans come on when the A/C is turned on.

[Classic Heartbeat]

Here is a discussion that I have commented on here before.. But here goes again.... How does placing a thermostat that turns your fans off and on do any good in the head of the engine? To my way of thinking this just doesn't work. Not at least the way that these trucks cooling system is designed to.
Why would you want your fans to come on when the water in the engine gets hot? Doesn't make sence to me? I want my fans to come on when the water in my radiator gets hot. After all that is the water your fans will be cooling when they come on.... True? We are not running air cooled engines, so the air that might flow across the engine when the fans come on will not cool it... If you think about it, what you want to happen when your engine reaches a certain temprature, lets say 180deg. you want that water to exchange for the cooler water in your radiator... True? Isn't that the function of the thermostat above your water pump?
Now think of this.... You have the thermostat for your fans located in the head of your engine... The water temprature reaches 180deg. and your fans come on.. Here's the problem.. Your thermostat for your water pump just opened up and excanged the cooled water from your radiator ito the hot engine to cool it down. True? Well then the fans shut off without cooling the water in the radiator, witch is what they are there for... True? What happens next time the water gets hot in the engine? Same thing only now you are exchanging hot water for hot water.... True? I am not doing this to start an argument, but for everyone to think about before (in my opinion) you make the mistake of buying a thermostat for your fans to place into the head of the motor. It needs to be in the radiator... WES www.ClassicHeartbeat.com

[mocwon]

Agreed, That's why I will have mine controled by the temp sensor than goes in the water neck of the radiator. In addition, the fans will come on when the A/C is turned on regardless of water temp.

QUOTE=WES]Here is a discussion that I have commented on here before.. But here goes again.... How does placing a thermostat that turns your fans off and on do any good in the head of the engine? To my way of thinking this just doesn't work. Not at least the way that these trucks cooling system is designed to.
Why would you want your fans to come on when the water in the engine gets hot? Doesn't make sence to me? I want my fans to come on when the water in my radiator gets hot. After all that is the water your fans will be cooling when they come on.... True? We are not running air cooled engines, so the air that might flow across the engine when the fans come on will not cool it... If you think about it, what you want to happen when your engine reaches a certain temprature, lets say 180deg. you want that water to exchange for the cooler water in your radiator... True? Isn't that the function of the thermostat above your water pump?
Now think of this.... You have the thermostat for your fans located in the head of your engine... The water temprature reaches 180deg. and your fans come on.. Here's the problem.. Your thermostat for your water pump just opened up and excanged the cooled water from your radiator ito the hot engine to cool it down. True? Well then the fans shut off without cooling the water in the radiator, witch is what they are there for... True? What happens next time the water gets hot in the engine? Same thing only now you are exchanging hot water for hot water.... True? I am not doing this to start an argument, but for everyone to think about before (in my opinion) you make the mistake of buying a thermostat for your fans to place into the head of the motor. It needs to be in the radiator... WES www.ClassicHeartbeat.com[/QUOTE]

[Classic Heartbeat]

That is where I stick the censor for our fan assemblies also and your right, the fans need to run full time when the A/C is on. WES www.ClassicHeartbeat.com

[Tim240Z]

One of the best value JY fans is from the late 80s ford taurus/sable. From the 3.8l engine. It is pretty flat, 2 speed and moves very serious CFM. I ran one in my 240Z with 94 f-body LT1 and a plastic/aluminum 4 cyl camaro radiator. Worked wonders!! I believe (sorry don't have the actual numbers in front of me) that the Taurus fan outflow the best flex-a-lite, or black magic fan by upwards of 20%. Can be gotten in any yard for $20-30.
just my 2c worth

[BobbyK]

WES,no worries man.
I figure if it's good enough for GM it's good enough for me.
I could care less what the temp in the rad is.As long as the block stays cool,that's all that matters with me

Everyone has their preferences.I prefer to wire this way.

[Classic Heartbeat]

Heck, I was just trying to get a good debate going and as always trying to get people to think about there trucks. I have always been the kind of guy that not only needs to know how something works, but why. (A product of my diognostic background I guess) So given that, I would just like to know how turning the fans on when the engine is hot does any good to cool the engine, giving the fact that the fans cool the water in the radiator. After all these engines are water cooled not air cooled. I am sure that having the censor in the head works, but it can't work verry efficiently. I think that GM must have used some sort of timers or something to keep the fans running, even though the water in the engine had dropped below the temprature setting. In that way they are turning the fans on at the same time the water exchanges. I could see that working. However without a timer or something of that nature, it would seem to me that once the water flushed through the engine, that the temprature of the water would drop below the set point, and the fans would shut off leaving the water in the radiator hot. I am sure that there is also some ambient cooling going on, especially while driving down the freeway and that helps also. Heck, you could go without fans of any sort while driving down the freeway as long as your radiator is not plugged. It is when we are doing a lot of stopping and going, towing, or stuck idling in traffic when we realy need the fans because then they pull or push the air accross the radiator cooling fins, that in turn cool the water. That would leave me to believe if you are doing any of the above, and your fans are turning off when the water is still hot in the radiator, you would eventually overheat reguardless of the fans. Anyway, I was just trying to see the logic, and was hoping that someone could enlighten me.. WES www.ClassicHeartbeat.com

[BobbyK]

WES,I'm sure you aware of this....but the sensor in the head is just an on/off switch,completing the fan circuit by being the ground.
That sensor has an effective temp. range that will ground the circuit.

Let's take the 3rd gen. Camaro's and Firebirds for example.
Fan control via the ECM with sensors in the head.
GM set the norm. operating temp at around the 200*F mark.With the 1st fan engageing at 225* and off at 220*the 2nd fan on only when temps reached the 240*F range and when the A/C was turned on.

Now having an E-fan cycle on and off frequantly puts a big demand on your charging system.Having a sensor that has a big enough working range can help keep things consistantly cool and lower the demand on the alt.

With a 180*F thermostat I'd say use a sensor that turns on at about 190*F and off at about 175*F

The thermal probes in the rad will read at least 10*F cooler than what the eng. is actually running.Though this depends on where you place your thermal probe.
For example.The probe in the rad would be set to turn on at 185*F and prob. does turn the fans on at that temp at the RAD,were-as the eng. temps are prob. 10-20*F hotter.
Useing a sensor in the head(in my opinion) gives you more accurate and consistant temp. readings.

There are aftermarket sensors that will let you trailor your on and off temps.All depends on the T-stat you running as well.

[chickenwing]

Boy, I really blew this thread to hell... Sorry Pat. You gotta admit, it is an interesting conversation though.

Wes, my thought on this is how long could the lag time in head temp and radiator temp be? If my fans kick on prior to rad temp equaling head temp, how is this a bad thing? Head temp will not immediately drop down to radiator temp requiring the fans to be turned off. The fans wont kick off until the radiator temp is equalized with the head shut off temp.

"Let's take the 3rd gen. Camaro's and Firebirds for example.
Fan control via the ECM with sensors in the head.
GM set the norm. operating temp at around the 200*F mark.With the 1st fan engageing at 225* and off at 220*the 2nd fan on only when temps reached the 240*F range and when the A/C was turned on."

Set like that, how does a 3rd gen camaro ever get down to 200?

BobbyK you raise up another good point in frequent cycling of fans. I have never tried adjusting mine. I realize now that I need to drop my shut off temp.

And since the topic is a little askew anyway.... I run a 165 degree stat. Anyone see any problems with that other than it not being altogether environmentally friendly?

[BobbyK]

It would all depend on the T-stat.Fans could shut off at 220 but if you had a 190 or 180 T-stat and you were traveling on the highway it would cool to whatever the T-stat is rated for.
Seems GM wanted to run those 3rd gen Camaro's a little warm.

Nothing wrong with a 165.You may not get as much hot air into the cab on those cold days as you would with a 175-180 but that's about it.

GM wanted those 3rd gen's to run hot for emission.

[tomatocity]

I have seen this photo before and it still scares me. That could really ruin your day.

Originally Posted by bobs409

Is this the pic your thinking of? This is what happened to the stainless steel flex fan on my truck. I was driving it at about 50 mph when it happened. It sounded like a boulder landed on my roof and then the truck started shaking like all heck, felt like I was riding on 4 flats. (out of balance fan after losing a blade)

Just glad I wasn't poking my head under the hood revving the engine when that happened.

BTW, that didn't just go through the flat steel, it also went through the under hood reinforcement! I had to remove it with a hammer!

This fan was on my truck when I bought it but I sure won't use anymore! They should be pulled from every shelf.

Anyone that is using one of these, I suggest you take it off now and throw it away.

[Classic Heartbeat]

I can see what you are trying to say, but the problem that I have with it is the engine teprature taken via the water in the engine, or any way on the engine doesn't have anything to do with the temprature of the water in the radiator. I say that because the untill the water in the radiator exchanges for the water in the engine one doesn't have anything to do with the other. Only in that the water needs to be cooled in the radiator befor it exchanges with the water in the engine. You have something between the two systems that acts as a wall and isolates one from the other and that is the engine's thermostat. The only way that it could be different is if you were not running a thermostat and your water is circulating all the time. That is not how our cooling systems run though.
You are right about the function and range of the e-fan thermostat, but as for the fans turning off and on frequently causing a drain on the electrical system, I don't see it. The fans only come on when the temp of the water in the radiator reaches the set temp of their thermostat, and that is what they are supposed to do. After all if they didn't the water wouldn't be cooled sufficently to cool the engine.
I guess the way I see it is you have an engine thermostat, and as long as the engine water temp is below the set temp of that thermostat, that water is isolated from the radiator water. Only when that water reaches the radiator can it be cooled sufficently to keep the engine at it's optimum running temp, or to keep it from overheating. The fans can kick on and off all they want and they will not effect the temp of the engine.

This is only an example, but I hope that it deminstrates my point.

Lets say that you are driving down the road and your engine temp reaches 165 and the thermostat for the engine is a 180 degree thermostat. The thermostat will not open up to alow the excange of radiator water for that of the water in the engine.. True?
Now lets say you have the fan thermostat set at 165 degrees, and that because you are driving down the road the temp of the water in your radiator is actually 120 degrees because of the air flow that is created driving down the road.
Now.... Do you want your fans to kick on? It would seem to me that if your fans were kicking on and off when they are not needed, that would be a bigger tax on the electrical system.
The only time that the fans need to kick on (unless you have A/C) is when the teprature of the water in the radiator gets higher than optimal running temp.
So given the fact that the engine thermostat isolates the water in the engine from the water in the radiator, what good does it do to turn the fans off and on according to the temprature of something that the fans are not cooling? When in fact the temp of the water in the radiator is allready cool.
The way that I see it is one does not have anything to do with the other untill the exchane is made. The only time you want your fans to come on is when the water in the radiator gets too hot and you can't tell the temprature of the water in the radiator with a probe in the engine. That's what seems logical to me. Anyway this is a great subject and it is great to get varrying points of view. WES www.ClassicHeartbeat.com

[tomatocity]

I can relate to both sides of measuring the engine water temp and the radiator water temp. If these trucks were computer driven I would have to agree with teh engine water temp. Since they are not computer driven I agree with the radiator. The only compensation we need is to cool the water in the radiator before it goes to the engine which will cool the engine. In most cases the water entering the engine will be hotter as it leaves the engine through the intake manifold. The engine thermostat would only be good to initially warm the engine to a proper operating temp and reduce the flow of water through the engine. The water has to stay in the radiator long enough to be cooled. Look at Jackson water pumps that are built for NASCAR. Other than being beefed up in other places the number of fins are reduced because they function at 8,000+ RPMs which would cause over cirulation or cavation if it were a normal water pump. It is not the speed of the water though the temperature of the water.

Originally Posted by WES

I can see what you are trying to say, but the problem that I have with it is the engine teprature taken via the water in the engine, or any way on the engine doesn't have anything to do with the temprature of the water in the radiator. I say that because the untill the water in the radiator exchanges for the water in the engine one doesn't have anything to do with the other. Only in that the water needs to be cooled in the radiator befor it exchanges with the water in the engine. You have something between the two systems that acts as a wall and isolates one from the other and that is the engine's thermostat. The only way that it could be different is if you were not running a thermostat and your water is circulating all the time. That is not how our cooling systems run though.
You are right about the function and range of the e-fan thermostat, but as for the fans turning off and on frequently causing a drain on the electrical system, I don't see it. The fans only come on when the temp of the water in the radiator reaches the set temp of their thermostat, and that is what they are supposed to do. After all if they didn't the water wouldn't be cooled sufficently to cool the engine.
I guess the way I see it is you have an engine thermostat, and as long as the engine water temp is below the set temp of that thermostat, that water is isolated from the radiator water. Only when that water reaches the radiator can it be cooled sufficently to keep the engine at it's optimum running temp, or to keep it from overheating. The fans can kick on and off all they want and they will not effect the temp of the engine.

This is only an example, but I hope that it deminstrates my point.

Lets say that you are driving down the road and your engine temp reaches 165 and the thermostat for the engine is a 180 degree thermostat. The thermostat will not open up to alow the excange of radiator water for that of the water in the engine.. True?
Now lets say you have the fan thermostat set at 165 degrees, and that because you are driving down the road the temp of the water in your radiator is actually 120 degrees because of the air flow that is created driving down the road.
Now.... Do you want your fans to kick on? It would seem to me that if your fans were kicking on and off when they are not needed, that would be a bigger tax on the electrical system.
The only time that the fans need to kick on (unless you have A/C) is when the teprature of the water in the radiator gets higher than optimal running temp.
So given the fact that the engine thermostat isolates the water in the engine from the water in the radiator, what good does it do to turn the fans off and on according to the temprature of something that the fans are not cooling? When in fact the temp of the water in the radiator is allready cool.
The way that I see it is one does not have anything to do with the other untill the exchane is made. The only time you want your fans to come on is when the water in the radiator gets too hot and you can't tell the temprature of the water in the radiator with a probe in the engine. That's what seems logical to me. Anyway this is a great subject and it is great to get varrying points of view. WES www.ClassicHeartbeat.com

[Boog]

Considering the flow of coolant I don't see where there will be much of any difference in when the fans will cycle on and off whether the sender is in the head or in the radiator. They are not that far apart. Where there is an adjustable thermostat used for the fans the point at which they cycle on can be changed. If one thinks it's necessary.
One way to narrow this debate down a bit is to ask Wes to test this deal out.
2 tests.
Using a digital temp gauge of some sort and the fan temp sender in the head then the temp sender in the radiator. Record the engine temp at the fan 'cycle on ' point versus the coolant temp in the radiator at the same time. Then report on the differences. That ought to do it.

[Classic Heartbeat]

The distance between the two places is completly irrelivent. Let me explain why.
The engines have a thermostat that acts like a big wall between the engine and the radiator. Water can not penatrate that wall because it seals off completely, or at least so much that any water that does happen to get around it is miniscule.
So if your engine is 180 degrees, and the water in the radiator is 140, why would you want your fans to kick on? The fans are not going to cool the water in the engine untill it makes it into the radiator. It won't do that untill the thermostat opens up to let it. Once that happens then the water in the radiator is 180 and the water that is in the engine is 140.
If the thermostat for the fans is located in the heads, you just shut the fans off with 180 degree water in the radiator. Now with the fans off how are you going to cool the water so that it is cool enough to go through the cycle again? WES www.ClassicHeartbeat.com