HP and/or fuel economy gains clutch fan vs e-fan

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Johnny248

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Does anyone have any real info on clutch fan's vs e-fan's? On a v8 engine, are there any gains to be had as far as horse power savings or increase in fuel economy from swapping a clutch fan to an electrical fan? I know that turning the fan uses energy, and when the clutch is engaged it is putting even more of a load on the engine while it is moving all that air. I also understand that putting a larger electrical draw on the alternator is going to use more engine HP to turn it also. That being said, the electric fan only runs when needed. The clutch fan still has to have some effect on engine power while it is spinning but not engaged.

Any real world experience?
 
you get increased acceleration, maybe a few hp at WOT(due to decreased drag).
theoretically A MPG increase but wont be very noticeable.

also the clutch fan moves ALOT of air.
buying an E-Fan big enough is expensive
 
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The engine has to supply mechanical energy to fan if belt driven.

The engine has to supply mechanical energy to the alternator which then supplies electrical energy to the electric fan.

The only advantages I see is closer temp control with the electric fan. That is, energy is only being consumed when the coolant temp really needs cooling and there is less drag.
 
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Most electric fans will turn off when you go over 30 mph or so. And only run under that for cooling if needed, usually over 200F.

AC will use the fan at all speeds depending on AC pressure.
 
E-fan below say, 35MPH will let temp go up and down too much for me. Clutch fan uses almost nothing when not engaged, will use some HP/MPG when engaged. Smaller engines will be more affected with clutch fan when engaged. Front engine cars have been using them forever with no issues, so the OEM's must be OK with them.
I had a 03 Dakota 3.9, factory clutch fan and electric fan. I took the clutch fan off in the winter and even then I could see temp going up/down in town.
 
Originally Posted By: OVERKILL
What's the application? A Mark VIII fan will cool pretty much anything.


'11 Ram Hemi. I ask because looking around the Ram forums, there is a pretty cool mod that people have been doing. The 5.7l comes with a clutch fan, and then a smaller electric fan on the radiator (this fan acts as the condenser fan, and then also kicks on if when the coolant temp reaches a certain temp as like a help fan)

Anyway, the 4.7l and 3.7l have one electric fan that mounts to the radiator and fits perfect in the Hemi rams, and is even plug and play. So you basically get rid of a clutch fan and a smaller electric fan in place of a new shroud/single fan setup. Cost is ~$100 for the fan. It looks much nicer and cleaner in the engine compartment. Gets rid of the giant shroud assembly. Just wondering how much if any performance or economy improvements that may be gained.
 
I ran without a clutch fan in my turbo volvo 940 for a few months, mostly just because the replacement water pump took a different style stud and I was lazy.

No noticeable change in performance.

Come to think of it, I never felt the drag of that fan anyway.
wink.gif
It had an electric pusher fan that came on with AC or with PCM command.
 
Originally Posted By: MolaKule
The engine has to supply mechanical energy to fan if belt driven.

The engine has to supply mechanical energy to the alternator which then supplies electrical energy to the electric fan.

The only advantages I see is closer temp control with the electric fan. That is, energy is only being consumed when the coolant temp really needs cooling and there is less drag.


Spot on...clutch fans are better than the old continuously blowing ones, but electrics can be completely out of the picture until needed, and are potentially (and probably) off at the time that maximum power is initially called for.
 
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Early Toyota camrys had a hydraulic fan that ran of the power steering pump system.
 
A nice feature of electric fans is they can easily be manually controlled by installing a switch that controls the fan relay coil, usually just grounding the coil will turn on the fan.
 
E fan can offer a VERY small improvement. Most newer engine driven fans have a thermostatic clutch that only cuts in at high temps. There is always a bit of parasitic drag though.

Newer E fan controllers offer variable or multiple speeds which allows for fewer "ups and downs" for coolant temps with a bit of tweaking.

Frankly you can bet if Dodge could save an MPG with an E fan they would have. That big fan is likely only needed in 90+ degree heat when towing a trailer or some other tough duty cycle.
 
Usually the OEM fan turn on temps are around 210F and off at around 200F. What you really need is a bigger radiator and more than likely the fan will seldom turn on unless you are sitting in traffic or the AC is on.

One problem Ford had and now my Hyundais have is the lo speed fan is for engine cooling and the hi sped fan is fr the AC. But when the lo speed fails for some reason the car then over heats. Ford changed this in 1996 with the Taurus. Don't know about their other cars.
 
Actually most newer cars have much more complex fan programs than that, even Fords.

Typically a low speed is on anytime the AC is. Then the high speed cuts in for things like excessive high side AC pressure, high coolant temps, or even trans fluid temps in slushbox equipped vehicles. Most will use a different program if AC is off and run the LS fans around 210 and the HS at 230 or so, varies by platform of course...
 
Originally Posted By: SteveSRT8
E fan can offer a VERY small improvement. Most newer engine driven fans have a thermostatic clutch that only cuts in at high temps. There is always a bit of parasitic drag though.

Newer E fan controllers offer variable or multiple speeds which allows for fewer "ups and downs" for coolant temps with a bit of tweaking.

Frankly you can bet if Dodge could save an MPG with an E fan they would have. That big fan is likely only needed in 90+ degree heat when towing a trailer or some other tough duty cycle.


Another thing I was looking at is the stat. A lot of guys are running 180 stats on their trucks and swear by them. They claim better mpg and performance saying that the pcm retards timing with the higher temperatures. I don't know. I've also read that on the 11+ trucks the colder stat can cause issues with codes and MDS cooperation, and claim the 203 is for emession reasons. It seems higher than needed, but I know that some others like gm use higher operating temps also. I was thinking king about going with a 190? Some where in between. When I watch my temp it climbs up to 203 then the stat opens and it drops down to about 190ish and repeats this cycle. You being the Chrysler guy,what do you think?

The main reason I was interested in the eFan is because it cleans IP the engine bay a lot, and it just seems cooler ( no pun intended ) than the old school fan setup.
 
You can put in 180F t-stats but unless the fan turn on temps are changed or you have a bigger radiator it won't do much good in the summer.

But my car came with a 180F t-stat.

On my car forum they try to sell 160F t-stats for the turbos but they can't even give them away.
 
Keep the cooling system in good shape If you have cooling problems in normal conditions, then there is a problem. Fix the problem, dont bandaid things with a work around. My car works fine in the winter without a clutch fan. It has an auxiliary electric fan when running the AC or over heats. Most engines these days have aluminum heads the warp easily.
 
Originally Posted By: SHOZ
You can put in 180F t-stats but unless the fan turn on temps are changed or you have a bigger radiator it won't do much good in the summer.

But my car came with a 180F t-stat.

On my car forum they try to sell 160F t-stats for the turbos but they can't even give them away.


My tuner allows me to change the cooling fan settings. I just don't think a jump all the way down to 180 is necessary.
 
Originally Posted By: andyd
Keep the cooling system in good shape If you have cooling problems in normal conditions, then there is a problem. Fix the problem, dont bandaid things with a work around. My car works fine in the winter without a clutch fan. It has an auxiliary electric fan when running the AC or over heats. Most engines these days have aluminum heads the warp easily.


Not having any cooling issues. Just a mod to change to the full efan setup. A lot of guys are dropping to a 180 t-stat claiming better performance and fuel econ.
 
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