Mechanical Fan VS Electric Fan

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T for sure. Brings engine to proper functional levels.
I think 180 is prob right, we are running a 160 high flow in the 440. It has factory elec fans / shroud and we had to mod them to run full time to keep the car reasonably cool and added the 160 T stat during the mod.
This "up to temp" allows the oil to flow properly rather than being too thick to provide proper pressure / volume in critical places and flow to the top end for that upper end type of oiling. Secondly temperature makes the tolerances proper. Thirdly temperature vaporizes pollutants in the oil and transmission such as fuel, water, and mysterious dissolved and suspended aromatic crap. The third benefit of proper operating temperature improves trans fluid and engine oil longevity considerably and eliminates damage caused by the pollutants because they "burn off".

I very much believe an up to temp non "pure drag" engine runs more efficiently both on power and fuel economy. The intake charge needs to be cooled but not the engine too much.

My rambling opinion :)

Hey, Plumcrazy, what is the application? What is your build and use?
 
This is my set up,
416 cu. 520 Hp, 904 Tran, 3.91 spool, Tranny cooler mounted in front of Radiator. OEM 22" radiator with a third core added. OEM shroud, Plastic flex a lite fan, No thermostat, running water with Red line Water wetter.
Runs 180 Deg to 200 Deg.
 

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Plumcrazy, what do you mainly do with the car? It appears to be mostly a strip car? Do you drive it to the strip or trailer it?

Good lookin engine / compartment.

Have you ever tested about a 160 or 180 thermostat (high flow)? Seeing that you are in Minnesota, you may find it advantageous to have the car warm up to temp more quickly. I would toss that plastic fan blade as they dont blow near as much air as a clutch fan (my opinion). If you are doing strip mainly, you may find it more advantageous to go with a non thermal clutch, I am pretty sure they just let slip when the engine is above about 3000 rpm letting the fan spin constant speed while the engine revs on up so as not to have too much drag.

http://www.summitracing.com/parts/MRG-4366/

Thermostat hi flow.
 
My car only has 45,000 miles on it, it's never seen winter. So my kids & I will cruise a bit localy, a few car shows & parades. We tow it to the drag strip 4 -6 times a summer. The closest one is 2 hours from my home. Theres so many different thoughts about cooling, I've been contiplating going to a electric water pump & electric radiator fan.
 
Rice Nuker said:
Seems like there should be some new cars you could get an elec fan setup off that would be pretty powerful and factory reliable and apparently fairly economical if a person was into the electric fans. I wonder if they would be sufficiently powerful enough for a big block..
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Yeah, I tried but it's very difficult to find an exact fit.

Rice Nuker said:
Very precise and nice, Mr. Ed.
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Thank you! :mrgreen:

Rice Nuker said:
Such as a hydraulic pump and a radiator fan run by a hydraulic motor? Think those are on some big diesel generators or some such. I believe I saw one when I was a kid. Sounds quite cumbersome for a car app I speculate :).
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My Grand Cherokee's fan runs on hydraulic pressure from the power steering pump. The pressure (and therefore fan speed) are regulated by the engine computer via solenoid! Different.
 
"My Grand Cherokee's fan runs on hydraulic pressure from the power steering pump. The pressure (and therefore fan speed) are regulated by the engine computer via solenoid! Different."

Whoa! What the heck? Wonder why in the world they wouldn't just run elec or direct. Wonder what possible reasoning they would have to do that.. Very interesting.

Holey crap. Did the Germans make automotive systems more complicated than ever necessary? Or was this a US design?
 

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So you delete the drag from the fan, and add power-robbing to the alternator. What power is picked up?
 
green1 said:
So you delete the drag from the fan, and add power-robbing to the alternator. What power is picked up?
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The drag generated at the alternator is nowhere near the same as the drag from a mechanical fan.
 
LXguy said:
The drag generated at the alternator is nowhere near the same as the drag from a mechanical fan.
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I would like to see some tests that support this statement. Apples to apples. In other words the electrical fans tested pulled the same volume of air that the clutch fan did.

Or another test would be to average the volume of air pulled and average the amount of HP required (over say 10 hours), since both thermo-clutch fan and electrical fans both do not pull consistent volumes of air.

If you move the same volume of air, how would there be less drag? You cannot do the same work and use less energy unless there is an efficiency increase right? An electrical fan scenario, you are turning the alternator which is like 70 - 80 % efficient, then running an electric motor that is similar in efficiency you have lost 40 % of your energy in the electrical process. Only if the electric fan blades were more efficient in ability would you gain some efficiency back. So, why not just put an equally efficient fan blade on the clutch and save 30 % of your used energy?

The only real way the electrical fan uses less energy is that they pull considerably less air, therefore using less rotational power at the alternator.
 
Rice Nuker said:
I would like to see some tests that support this statement. Apples to apples. In other words the electrical fans tested pulled the same volume of air that the clutch fan did.

Or another test would be to average the volume of air pulled and average the amount of HP required (over say 10 hours), since both thermo-clutch fan and electrical fans both do not pull consistent volumes of air.

If you move the same volume of air, how would there be less drag? You cannot do the same work and use less energy unless there is an efficiency increase right? An electrical fan scenario, you are turning the alternator which is like 70 - 80 % efficient, then running an electric motor that is similar in efficiency you have lost 40 % of your energy in the electrical process. Only if the electric fan blades were more efficient in ability would you gain some efficiency back. So, why not just put an equally efficient fan blade on the clutch and save 30 % of your used energy?

The only real way the electrical fan uses less energy is that they pull considerably less air, therefore using less rotational power at the alternator.
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The test might have some validity if you were just testing the fans. Ultimately, what we are looking for is the efficiency of the cooling system.

The implied massive and equalizing load that you are talking about on the alternator would only be imposed by an electric fan of the same cfm rating working at the same rate as your beloved mechanical clutch fan. The rotational mass of the charging system remains constant. It's the imposed load that varies. With an electric fan, you reduce the the mass of the fan/clutch/pulley/belt/bolts/dust/six bugs/whatever from the engine. By default, the engine benefits from less rotational mass from the onset.

So, perhaps a better test would be to see how much airflow is required for your cooling system to operate efficiently and plan your fan set up from there?
 
Per request,
I'm running a 12.5 to1 comp 440, with aluminum heads. I have a CSR electric pump, and BeCool radiator and dual 12" fans with shroud. The fans are thermostatly controled but I also wired in a seperate on/off for the fans.
The advantages of this set up is I can shut the engine off, and still circulate and cool the system. We all know how temps spike after the engine is shut down, I dont have that issue.
I went with the BeCool system because they offered the whole system with an oversized radiator that was a drop in and properly cleared the waterpump.
I'm already running an internally regulated alternator so the draw wasnt an issue.
I noticed in your post your not running a t/stat. I'm a firm believer in the fact that you need some sort of restriction in the system. Like a t/stat.
I'm using a restricter disc.
My system was pricey, about $1700 complete, but it cured my problem, and looks good.
 

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Plumcrazyfreak said:
This is my set up,
416 cu. 520 Hp, 904 Tran, 3.91 spool, Tranny cooler mounted in front of Radiator. OEM 22" radiator with a third core added. OEM shroud, Plastic flex a lite fan, No thermostat, running water with Red line Water wetter.
Runs 180 Deg to 200 Deg.
Click to expand...

Now im leaning towards purple for my car with this color :tongue9:
 
Revhendo,

"So, perhaps a better test would be to see how much airflow is required for your cooling system to operate efficiently and plan your fan set up from there?"

Agreed.

Additionally I would not imagine that the factory fan system would be overkill to the extent that it needs revision. There would be no reason for the factory to produce a significant overkill on a system. Secondly it is stone reliable. Then add on the increase in performance of the modified engine and it seems reasonable that a person would not be interested in less than factory cfm.

"The implied massive and equalizing load that you are talking about on the alternator would only be imposed by an electric fan of the same cfm rating working at the same rate as your beloved mechanical clutch fan."

True. I do love mechanical fans. I also very much like a lot of the awesome electrical fan setups posted here as they really look aerospace and bad ***. I agree with your statement above that the best test would be to determine the optimum cfm and water flow for an application.

"With an electric fan, you reduce the the mass of the fan/clutch/pulley/belt/bolts/dust/six bugs/whatever from the engine."

I partially agree.

Every time the elec fan cycles it burns energy getting up to speed so that is load. While it is running of course that is load. You still have a pulley and belt on the water pump so that rotational inertia is the same on those components even if you delete the clutch fan. In an electric fan scenario you have considerable loss of energy in translating rotational energy to electrical energy in the alternator then back to its original state in the elec fan motor. So there is loss of efficiency that cannot be applied to generating cfm. Simply changing to a modern plastic fan blade such as on a ford ranger could alleviate the stigma of a moderately efficient factory metal fan blade further increasing the net efficiency of a clutch fan set up.

I would be willing to bet if you had an electric fan that pulled the same as the stock clutch fan it would burn more horse power if you averaged it out over a 10 hour period.

I could of course be very wrong due to other factors that I am not accounting for. One could be that in an efficiently designed air flow system where an air dam and bumper contour promotes great air flow thru the radiator during driving speeds, an electric fan can completely turn off for potentially hours at a time producing zero crankshaft drag and make up for its inefficiencies, operating only at low vehicle mph. Not sure if that is a real world scenario though.

I still say that the only reason an electrical fan would use less energy is because it is yielding less work (cfm) therefore requiring less energy input. Same concept with an electric water pump.

Like you said, the question is how much yield is necessary to properly cool the engine in the application.
 
Rice Nuker said:
Revhendo,

"So, perhaps a better test would be to see how much airflow is required for your cooling system to operate efficiently and plan your fan set up from there?"

Agreed.

Additionally I would not imagine that the factory fan system would be overkill to the extent that it needs revision. There would be no reason for the factory to produce a significant overkill on a system. Secondly it is stone reliable. Then add on the increase in performance of the modified engine and it seems reasonable that a person would not be interested in less than factory cfm.

"The implied massive and equalizing load that you are talking about on the alternator would only be imposed by an electric fan of the same cfm rating working at the same rate as your beloved mechanical clutch fan."

True. I do love mechanical fans. I also very much like a lot of the awesome electrical fan setups posted here as they really look aerospace and bad ***. I agree with your statement above that the best test would be to determine the optimum cfm and water flow for an application.

"With an electric fan, you reduce the the mass of the fan/clutch/pulley/belt/bolts/dust/six bugs/whatever from the engine."

I partially agree.

Every time the elec fan cycles it burns energy getting up to speed so that is load. While it is running of course that is load. You still have a pulley and belt on the water pump so that rotational inertia is the same on those components even if you delete the clutch fan. In an electric fan scenario you have considerable loss of energy in translating rotational energy to electrical energy in the alternator then back to its original state in the elec fan motor. So there is loss of efficiency that cannot be applied to generating cfm. Simply changing to a modern plastic fan blade such as on a ford ranger could alleviate the stigma of a moderately efficient factory metal fan blade further increasing the net efficiency of a clutch fan set up.

I would be willing to bet if you had an electric fan that pulled the same as the stock clutch fan it would burn more horse power if you averaged it out over a 10 hour period.

I could of course be very wrong due to other factors that I am not accounting for. One could be that in an efficiently designed air flow system where an air dam and bumper contour promotes great air flow thru the radiator during driving speeds, an electric fan can completely turn off for potentially hours at a time producing zero crankshaft drag and make up for its inefficiencies, operating only at low vehicle mph. Not sure if that is a real world scenario though.

I still say that the only reason an electrical fan would use less energy is because it is yielding less work (cfm) therefore requiring less energy input. Same concept with an electric water pump.

Like you said, the question is how much yield is necessary to properly cool the engine in the application.
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For the record, I still use stock clutch fans for most of MY cars. Gonna have to rethink it if I get to the LS swap in the fishing truck.

FWIW, I don't think electric fans have to pull as much cfm due to being attatched directly to the radiator as opposed to being mounted away from it and needing a larger tunnel like shroud. No clue really, just guessing. I do know that a properly working electric fan on a good cooling system will aid in engine warm up. It will also cycle at an idle and almost never come on in steady state driving. That could be the hp and milage advantage.
 
nerd scientist here. 30 amps out of a normal alternator is a little under 1 hp of draw taking into account average efficiencies.
 
jerame_c said:
nerd scientist here. 30 amps out of a normal alternator is a little under 1 hp of draw taking into account average efficiencies.
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It requires less than 1 horse power to make 320 watts? I am setting up a wind mill to run my shop off a car alternator. My shop has 12 flourescents and a small radio. Should run that off a 100 amp alternator, in a hurricane..

This in interesting, taken off this website:

3. Thou shall use an electric fan.
Rule of thumb. Only choose a mechanical fan over an electric fan if it’s your farm tractor. An electric fan is preferred because when you need a fan the most (at idle or cruising speeds) an electric fan is delivering maximum air independent of engine RPM’s. Fans that move 2000-2300 CFM’s are worth the investment. Preference should be given to a “pull” vs. a “push” fan. Mounted on the engine side of the radiator, a pull fan does not interfere with air flow at highway speeds. All shrouded fans should be on the engine side of the radiator.


http://www.carolinarodshop.com/Store/Griffin/radiator_10_commands.htm

someone posted it on this site and I just posted it here, so I am being a parrot I reckon.
 
If everything was 100% efficient, 1 horsepower = 745.7 watts = 55.2 amps at 13.5 volts.

Also 30 Amps at 13.5 volts = 405 watts.

Your 12 fluorescence lamps (assuming 60 watts each) draw a total of about 6.5 amps at 110 volts.

Just sayin', 'cause I'm bored and can't sleep. :toothy7:
 
Can I add my 2 cents worth to this whole thought pattern?
1) having a properly sized radiator to the engine output is key- no matter how much air goes thru; if you pass 10,000 cfm thru too small or a non-efficient radiator (meaning the heat transfer is too slow to escape the coolant and into air) the car will over heat. Why do they paint radiators anyhow? it slows heat transfer.
2) it is easier on the alternator to make power than a mechanical fan- ask one... sit in front of an electric fan running on a hot day and then walk away and use a mechanical fan (yes like a geisha girl from the orient) which one is easier. (LOL!)
3) Electric fans are cheaper to build and weigh less and more controllable than a mechanical fan. That's why manufactures are using them. Plain economics. PLUS how do you cool a radiator with a transverse engine? ( engine sits sideways in the car like a front wheel drive?)
4)if it is personal preference: personally i like the mechanical fan with a back up electric for those lazy hot days.

Soap box is yours- who's next?
 
1968FormulaS340 said:
For a track car....... Sure. But not the best choice for a dedicated street car.
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So, people that are NOT going with an electric pump when going electric fan...they are just removing the fan/clutch, leave the pulley on the water pump? Mechanical fans work fine. But, electric does clean up the bay I guess.
 
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