Electric fan Vs. Mechanical fan (split from Chris' e-fan thread)

[Skandocious]

Okay let me try a different approach here Greg...

I will agree that you are CORRECT (yes you heard me) in that an efan may not (and probably WILL NOT) be suitable in a heavy duty application. I have not disputed this point. The point I'm trying to defend, and hence trying to get you to ACKNOWLEDGE, is the fact than an efan like mine, Ricks, Ryan's flexalite, etc-- is MORE than suitable for a stock/slightly modified 351w 1/2 ton truck. You alluded to it here:

FYI 220 hp is not much.

Sure it ain't that much-- but it's what OUR engines are putting out (or at least rated for). We are merely contending that these fans our suitable for OUR applications. I, nor any other efan supporters in this thread, ever tried to imply that big rigs and F450 car haulers should be running efans. If I said something to that tune then please quote it for me so I can retract it.

If you can agree that we (us 1/2 ton, near-stock engine, drivers) are safe using high powered efan on our trucks, then there is nothing more to argue about.



Lastly-- do not bring my intelligence into question. This is not a battle of wits; it's about laying out what we know and having a civilized discussion in order to spread knowledge to those who may not know certain details about the subject at hand (you and me included). I never took shots over your bow, please do me the same respect.

 

[blackhat620]

Okay let me try a different approach here Greg...

I will agree that you are CORRECT (yes you heard me) in that an efan may not (and probably WILL NOT) be suitable in a heavy duty application. I have not disputed this point. The point I'm trying to defend, and hence trying to get you to ACKNOWLEDGE, is the fact than an efan like mine, Ricks, Ryan's flexalite, etc-- is MORE than suitable for a stock/slightly modified 351w 1/2 ton truck. You alluded to it here:

Sure it ain't that much-- but it's what OUR engines are putting out (or at least rated for). We are merely contending that these fans our suitable for OUR applications. I, nor any other efan supporters in this thread, ever tried to imply that big rigs and F450 car haulers should be running efans. If I said something to that tune then please quote it for me so I can retract it.

If you can agree that we (us 1/2 ton, near-stock engine, drivers) are safe using high powered efan on our trucks, then there is nothing more to argue about.

Chris in certain applications e-fans will work fine. I will not make a blanket statement that in all 1/2 ton near-stock engine trucks, drivers are safe using high powered e-fans in all conditions. There are to many variables and options that may or may not allow the e-fan to provide sufficient cooling even in 1/2 ton trucks. I have seen e-fans not work in some 1/2 ton stock trucks in the desert southwest and i have seen them work in others. Problem is there were more than one radiator option, engine option and transmission option through the years.

Lastly-- do not bring my intelligence into question. This is not a battle of wits; it's about laying out what we know and having a civilized discussion in order to spread knowledge to the unknowing (you and me included). I never took shots over your bow, please do me the same respect.

Chris i did not call your intelligence into question (and if you thought i did i apologize). I questioned your knowledge & experience in this area, this is quite different than questioning your intelligence.

 

[Bob Ayers]

Here is the bottom line, the way I see it:

1) E-fans don't have the cooling capacity of the OEM mechanical fan/clutch.
Vehicles designed to have an e-fan have larger capacity radiators to compensate for the reduced air flow of the e-fan.

2) Any performance / MPG increase with an e-fan will be minimal, if any, if the mechanical fan clutch is working properly

3) E-fans are far less reliable than the mechanical fan/clutch, simply due to the number of components, and the associated failure rate of each component.

 

[NeXtras]

dam, 8 pages huh? lol.. your all forgetting one crucial thing, except skan, the amound of air the fan can moves depends on TWO things, 1 being its rotation speed and two being the pitch of the blades, if ou havent noticed, the blades on an efan are pitched quite a bit, they can also spin pretty quick due to the design of the electric motors (virtually no friction)...

To be honest, look at most of the cars you see at the drag strip, what do they have? ELECTRIC COOLING FANS! They also have ELECTRIC water pumps (if built correctly of course)

Vehicles designed to have an e-fan have larger capacity radiators to compensate for the reduced air flow of the e-fan.

Theres another thing, these trucks (1/2 ton near stock) have BIG radiators! They get hot, yes, but its pretty hard for the engine to overheat with that big ass thing (assuming you have correct fluid levels, good radiator etc etc.)

If you have a FUNTIONAL water temp gauge, your all set with an E-fan, just monitor the temp, if its getting a little too hot for your liking, turn the fan off auto and onto ON, an e-fan running constantly still uses LESS power than a normal, engine driven, clutched fan.... not to mention the fan clutches on these are prone to problems!


I find it wrong that blackhat attacked Skan.. and YES you did question his inteligence, and actually you belittled him. In Skans defense, he's quite a knowledgeable guy, in almost EVERY thread i have on here with a question, take a guess who the first person to reply was, and with an answer i might add... SKAN!

Having run forums for a number of years, blackhat you were just flaming... which isnt tolerated on many forums... please, please, please stop, and tone it down... re-read what you wrote, you most certainly DID question his intelligence and you based it purely on age!

 

[Bob Ayers]

dam, 8 pages huh? lol.. your all forgetting one crucial thing, except skan, the amound of air the fan can moves depends on TWO things, 1 being its rotation speed and two being the pitch of the blades, if ou havent noticed, the blades on an efan are pitched quite a bit, they can also spin pretty quick due to the design of the electric motors (virtually no friction)...

To be honest, look at most of the cars you see at the drag strip, what do they have? ELECTRIC COOLING FANS! They also have ELECTRIC water pumps (if built correctly of course)



Theres another thing, these trucks (1/2 ton near stock) have BIG radiators! They get hot, yes, but its pretty hard for the engine to overheat with that big ass thing (assuming you have correct fluid levels, good radiator etc etc.)

If you have a FUNTIONAL water temp gauge, your all set with an E-fan, just monitor the temp, if its getting a little too hot for your liking, turn the fan off auto and onto ON, an e-fan running constantly still uses LESS power than a normal, engine driven, clutched fan.... not to mention the fan clutches on these are prone to problems!


I find it wrong that blackhat attacked Skan.. and YES you did question his inteligence, and actually you belittled him. In Skans defense, he's quite a knowledgeable guy, in almost EVERY thread i have on here with a question, take a guess who the first person to reply was, and with an answer i might add... SKAN!

Having run forums for a number of years, blackhat you were just flaming... which isnt tolerated on many forums... please, please, please stop, and tone it down... re-read what you wrote, you most certainly DID question his intelligence and you based it purely on age!

In addition to the pitch of the blades, the blade area is also important! Check out the blade area on the mechanical fans.

Also, due to the lack of "pull" from e-fans, the aftermarket e-fan manufacturers don't recommend using an e-fan with 4 core radiators.

 

[surewhynot]

That leaves me curious about factory fans. Aftermarket ones keep getting mention, but nobody is talking about using them.

 

[NeXtras]

They wouldnt make kits for it if they wouldnt work..

a fans a fan.. the e-fan will work fine.. like i said, takes alot to make one of these trucks overheat

 

[surewhynot]

Tony,

You have multiple issues going on here, and without checking sizes, the F250 radiator you installed may have been the larger than needed for your engine application. In addtion, i will give you that 15k is heavy, but you live where you have relatively high humidity which aids in cooling. Bring your truck to the deserts of West TX, NM, AZ or Southern CA and you may find with the high ambiant temps and low humidity that your system is not up to the task. Without testing in these conditions we will not know for sure. Unfortunately i have seen e-fan setups not cool properly in the Desert Southwest, under high loads & ambient temperatures. There is a reason all the auto manufactures came to the AZ desert to build there proving grounds and test tracks.

On a side note AC systems for houses and buildings are switching to the new "greener" R-410 refrigerant. Well the draw back to R-410 is excessively high head pressures. These units work well everywhere but the desert southwest (this is a closely concealed fact by the HVAC industry). In the desert southwest the HVAC units with R-410 reach there high pressure limit switch rating on high temp days and cycle off to prevent the compressor from failing. The engineers are making strides to try and fix this "little" problem but so far if you want your HVAC to work on high heat days in the desert southwest you need to run units using the old reliable R-22. Hopefully by the time R-22 is no longer produced in 2020 they will have this problem fixed.

Bottom line of all this is that the Desert Southwest's high temperatures are extremely hard on equipment. Think of the polar opposite of Alaska in February.

The point of my post was that I didn't know any better. It never crossed my mind that an electric fan may not pull enough in a heavier truck. Like you said, the radiator may have been overkill for the engine. It was the largest 4 core radiator I could fit, but seeing as the engine was available in F250's, I thought it would be a good match. I really doubt it was larger than needed, since I took an engine that was available with that radiator in a lighter truck and put it in a heavier truck.

Where you live, it would be a task to keep anything cool. I wouldn't want to imagine trying to put together a system that works. I am not arguing that it wouldn't work there. I was just posting what I have done here, befoer I even knew to question the setup.

I still wonder if factory fans are higher quality than aftermarket ones. With parts, it tends to go that way alot.

 

[big5oh]

First off mechanical clutch fans are NOT 100% efficient and neither are e-fans. Heavy duty mechanical clutch fans are 90% efficient, and lighter duty clutch fans are 75-80% effiecient. That being said, e-fans are not 100% efficient either as i posted earlier. E-fans CFM rating drops 15-30% from the published data when the air is pulled through a radiator (pusher fans drop an additional 15%). This translates to e-fans being 70-85% efficient when used as a puller, and 55-70% when used as a pusher.

How do you explain a mechanical fan being inefficient? For every bit of parasitic added to accessory drive by a mechanical fan you get a proportional amount of air flow....there is no loss involved. Wether or not you need the airflow at all times that the fan is spinning is another story.

 

[big5oh]

Chris, you are correct, a mechanical fan clutch does not fully disengage, as there is always some drag, in fact it is about 20%.

According to fan clutch manufacturers they spin at 60% of water pump speed..........so that would be a drag of 60%, not 20% assuming that the manufacturer's data is accurate.

 

[blackhat620]

How do you explain a mechanical fan being inefficient? For every bit of parasitic added to accessory drive by a mechanical fan you get a proportional amount of air flow....there is no loss involved. Wether or not you need the airflow at all times that the fan is spinning is another story.

It is a simple law of physics. The mechanical fan clutch is anywhere from 70-90% efficient when fully engaged depending on the design they never fully lock up since they are fluid coupling. Think of a torque converter.

According to fan clutch manufacturers they spin at 60% of water pump speed..........so that would be a drag of 60%, not 20% assuming that the manufacturer's data is accurate.

When the fan clutch is fully disengaged it still spins at abouth 20% of the water pump speed, again this is do to the fluid coupling design and friction. The fan clutch is never fully disengaged do to the type of coupling.

It is a proven fact on the race track that an e-fan will lower your ET's and increase your MPG over a mechanical clutch fan. E-fans have there applications a uses. The draw back to an e-fan is that they do not have the air flow capacity needed under "Heavy Loads & High Ambiant temperatures".

 

[blackhat620]

The point of my post was that I didn't know any better. It never crossed my mind that an electric fan may not pull enough in a heavier truck. Like you said, the radiator may have been overkill for the engine. It was the largest 4 core radiator I could fit, but seeing as the engine was available in F250's, I thought it would be a good match. I really doubt it was larger than needed, since I took an engine that was available with that radiator in a lighter truck and put it in a heavier truck.

Where you live, it would be a task to keep anything cool. I wouldn't want to imagine trying to put together a system that works. I am not arguing that it wouldn't work there. I was just posting what I have done here, befoer I even knew to question the setup.

I still wonder if factory fans are higher quality than aftermarket ones. With parts, it tends to go that way alot.

Tony,

I think we alot of us have been down the road you went down when we build up a toy etc. Alot of it is trial and error to find the right components for the application. E-fans have there applications and needs, but like everything else they have there limitations. It all gets down to trade offs for the application at hand.

IMO some aftermarket e-fans are built to the same quality of factory e-fans, but i believe a majority of the AM e-fans are substandard at best when it comes to build quality. I do not have any test data on this but alot of the AM e-fans i have seen are poorly built IMO.

Yep the Desert Southwest is definitely and oven in the summer and we find the weak link in things quickly.

 

[blackhat620]

Here is the bottom line, the way I see it:

1) E-fans don't have the cooling capacity of the OEM mechanical fan/clutch.
Vehicles designed to have an e-fan have larger capacity radiators to compensate for the reduced air flow of the e-fan.

Agreed with one caveat, the lighter duty mechanical clutch fans CFM rating can be matched by some e-fans. Where mechanical clutch fans shine is in High Heat large CFM requirements.

2) Any performance / MPG increase with an e-fan will be minimal, if any, if the mechanical fan clutch is working properly

It has been proven on the race track you will get lower ET's & higher MPG with an e-fan as they provide less drag on the motor. This will translate in to better performance & mpg on your DD, the amounts are going to vary on each application.

3) E-fans are far less reliable than the mechanical fan/clutch, simply due to the number of components, and the associated failure rate of each component.

I understand the fewer components argument, but in the real world daily use the OEM e-fans & mechanical clutch fans have about the same life span 80-100k miles. I have not found one to be more reliable than the other on DD at least in the Desert Southwest.

 

[surewhynot]

Tony,



IMO some aftermarket e-fans are built to the same quality of factory e-fans, but i believe a majority of the AM e-fans are substandard at best when it comes to build quality. I do not have any test data on this but alot of the AM e-fans i have seen are poorly built IMO.

We pretty much share that opinion. With alot of the junk that is on the market nowdays, it makes it hard to tell who makes a quality product anymore. I don't mean to bash all the aftermarket manufacturers, but a few have given many a bad name unfortunately.

 

[blackhat620]

dam, 8 pages huh? lol.. your all forgetting one crucial thing, except skan, the amound of air the fan can moves depends on TWO things, 1 being its rotation speed and two being the pitch of the blades, if ou havent noticed, the blades on an efan are pitched quite a bit, they can also spin pretty quick due to the design of the electric motors (virtually no friction)...

Yes blade pitch, size and speed determine the amount of air moved, a mechanical clutch fan can pull more air than an e-fan do to the simple fact you can put a more aggressive fan blade on the large engine that is driving it. There is just not the physical space and electrical capacity on vehicles to make and e-fan that can pull the CFM's of a large mechanical clutch fan.

To be honest, look at most of the cars you see at the drag strip, what do they have? ELECTRIC COOLING FANS! They also have ELECTRIC water pumps (if built correctly of course)

This has been mentioned numerous times in this thread and yes e-fans have there use and applications. We do not run any radiator or fans (electric or mechanical) on our drag cars.

Theres another thing, these trucks (1/2 ton near stock) have BIG radiators! They get hot, yes, but its pretty hard for the engine to overheat with that big ass thing (assuming you have correct fluid levels, good radiator etc etc.)

If you have a FUNTIONAL water temp gauge, your all set with an E-fan, just monitor the temp, if its getting a little too hot for your liking, turn the fan off auto and onto ON, an e-fan running constantly still uses LESS power than a normal, engine driven, clutched fan.... not to mention the fan clutches on these are prone to problems!

Try that in the summer in the Desert Southwest were our overnight lows do not go below 105F for weeks at a time. Sorry but you can overheat out here fairly easily in the summer if the cooling system is not up to the task. Large radiators help, but they also require proper air flow which requires a high CFM rate. There is a reason all of the auto manufactures and heavy equipment manufactures finally built testing/proving grounds in the AZ desert.
If the e-fan is set to "auto" and is running, how is turning the switch to "on" going to increase the air flow of the already running fan? Factory e-fans and mechanical clutch fans are rated for 80-100k miles the same as water pumps. Both the e-fans & mechanical fan clutches fail at about the sme rate.

I find it wrong that blackhat attacked Skan.. and YES you did question his inteligence, and actually you belittled him. In Skans defense, he's quite a knowledgeable guy, in almost EVERY thread i have on here with a question, take a guess who the first person to reply was, and with an answer i might add... SKAN!

Having run forums for a number of years, blackhat you were just flaming... which isnt tolerated on many forums... please, please, please stop, and tone it down... re-read what you wrote, you most certainly DID question his intelligence and you based it purely on age!

Couple of things, first open your dictionary and look up "Intelligence" & "Knowledge". They have completely different meanings. Yes i am questioning Chirs's "Knowledge & Experience" in some of his statements, wether you like it or not the simple fact of Chris's age limits his experience and knowledge base in some of these applications.

Second, since when does how fast or often someone posts automatically make there answer correct? Your argument sounds like you are basing the correctness of an answer on the number & speed of posts the poster has?Based on your argument Chris should automatically be the smartest and most knowledgeable person on this forum since he has the highest post count.

They wouldnt make kits for it if they wouldnt work..

a fans a fan.. the e-fan will work fine.. like i said, takes alot to make one of these trucks overheat

If a company selling a product thinks they can make a dollar selling something they will. It does not have to work for crap. Fuel line magnets, vortex intake air swirlers come to mind. In the real world "Caveat Emptor", or as PT Barnham said "there is a sucker born every minute".

Sorry but "a fans a fan.." is not a true statement. The fan must be matched to the application & use. Based on your theory i can take a fan off of a 85 Corolla and install it in my Super Duty and never have cooling issues, especially since the truck has a "Large" radiator. In the Desert Southwest it does not take much to make a vehicle (read that "any vehicle") over heat in the summer.

 

[blackhat620]

We pretty much share that opinion. With alot of the junk that is on the market nowdays, it makes it hard to tell who makes a quality product anymore. I don't mean to bash all the aftermarket manufacturers, but a few have given many a bad name unfortunately.

Exactly, the "roaring 20's" of the last 15 years has produced a lot of mergers and start-ups that are producing crap just to relieve the un-suspecting of there hard earned cash. Alot of old time good company names that produced high quality parts have been bought out and then the quality was lowered to substandard.

 

[big5oh]

It is a simple law of physics. The mechanical fan clutch is anywhere from 70-90% efficient when fully engaged depending on the design they never fully lock up since they are fluid coupling. Think of a torque converter.

Explain what accounts for the inefficiency.

When the fan clutch is fully disengaged it still spins at abouth 20% of the water pump speed, again this is do to the fluid coupling design and friction. The fan clutch is never fully disengaged do to the type of coupling.

Where do you get that number? The OEM replacement units that I have seen in the past for the applications relevant to this forum have always advertised that they spin at 60% of water pump speed. This is of course when they are new.........as they age, who knows where exactly they would be. I am under the assumption we are talking about known good parts, not worn-out-and-in-need-of-replacement parts.

 

[blackhat620]

Explain what accounts for the inefficiency.

Friction, heat, slippage. Nothing is 100% efficient. Fluid couplings always have a slippage loss. Torque converter is perfect example. The reason torque converts no have a "Locking" feature is to up the efficiency of the final drive resulting in better mpg. Here is a link to a torque converter operation.
http://auto.howstuffworks.com/auto-parts/towing/towing-capacity/information/torque-converter.htm


Where do you get that number? The OEM replacement units that I have seen in the past for the applications relevant to this forum have always advertised that they spin at 60% of water pump speed. This is of course when they are new.........as they age, who knows where exactly they would be. I am under the assumption we are talking about known good parts, not worn-out-and-in-need-of-replacement parts.

There are two types of fan clutches "Thermal & Non-Thermal". Non-Thermal fan clutches always spin at 60% of the water pump speed regardless of ambiant temperature. Thermal clutches spin anywhere from 20% - 90% of water pump speed depending on the ambiant temperature coming through the radiator.

There are three grades of Thermal clutches, Standard duty spin at 50-60% water pump speed when fully engaged; Heavy duty spin at 80-90% of water pump speed when fully engaged and have a fin surface area of approx 47 sq in; Severe duty spin at 80-90% of water pump speed when fully engaged and have a fin surface area of approx 65 sq in. The larger surface area allowes the fan clutch to operate more efficiently and have a longer life span in High heat & load applications.
www.haydenauto.com/installation/faqs.htm

All Thermal fan clutches still spin at approx 20% of water pump speed in cold ambiant temperatures (ie disengaged.
Non-Thermal fan clutches spin at 60% of water pump speed regardless of ambiant temperature.

 

[Bob Ayers]

understand the fewer components argument, but in the real world daily use the OEM e-fans & mechanical clutch fans have about the same life span 80-100k miles. I have not found one to be more reliable than the other on DD at least in the Desert Southwest.

Are you just comparing the clutch to the electric motor/fan? There are a lot of other components like wiring and connectors, controller, relays, fuses, and
temp sensor.

One other difference, the main failure mode with a clutch is it locks up. With this failure mode, you still have cooling. With an e-fan, chances are real good that if something fails, you loose cooling.

 

[NeXtras]

Try that in the summer in the Desert Southwest were our overnight lows do not go below 105F for weeks at a time. Sorry but you can overheat out here fairly easily in the summer if the cooling system is not up to the task. Large radiators help, but they also require proper air flow which requires a high CFM rate. There is a reason all of the auto manufactures and heavy equipment manufactures finally built testing/proving grounds in the AZ desert.
If the e-fan is set to "auto" and is running, how is turning the switch to "on" going to increase the air flow of the already running fan? Factory e-fans and mechanical clutch fans are rated for 80-100k miles the same as water pumps. Both the e-fans & mechanical fan clutches fail at about the sme rate.

now the majority of us DONT live in a desert! so your friggin theory is bull to us... and ive never heard there be a 80k-100k warning on a waterpump, or fan... im 200k strong and neither has givin me trouble...

and im pretty sure someone on here, there fan clutch actually wouldnt engage,.. and another was the clutch was always engauged..


your just attacking people here.. and y the hell would you run no fan at all on a drag car.. if you want to hot lap you need to cool that sucker down... easiest way is to have the e-pump and e-fan going while car is off..

ALL IN ALL let skan do what he wants, and others as well

AND I DONT CARE WHAT YOU SAY you definetly insulted skan with an inteligence remark.. do you even know how old he is? and how old are you?


**by the way, what is the CFM of a normal engine fan on these?