Mechanical cooling fan vs electric

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I had one of those steel flex fans once and use to run my Ford Torinos with a 302 with no fan. I do 95% highway driving.
 
I wonder why mechanical fans are still in use with the availability and benefits of electric fans.
Good video though, illustrates how much difference can be made by something you wouldn't normally give a lot of thought to.
 
Easiest job I ever did was belt/hoses on a 4.3L GMC with electric fans ... talk about space to work.
 
Originally Posted By: Olas
I wonder why mechanical fans are still in use with the availability and benefits of electric fans.
Good video though, illustrates how much difference can be made by something you wouldn't normally give a lot of thought to.


Extreme cooling requires extreme CFM, something that no electric fan can do compared to a proper mechanical, engine driven fan.
 
Originally Posted By: skyactiv
Where the electric fan at?


Let's say your electric fan pulls 40 amps and your alternator voltage is 14. That's 560watts which is about 3/4 hp
 
I believe that an electric fan is the only one that tells you that your oil viscosity choice is a good one.
 
My one car with a mechanical cooling fan has it directly attached to the water pump(via a V-belt that also drives the alternator). There is no clutch.

I've considered installing electric fans. To my way of thinking, there two deficiencies in mechanical fans that aren't present in electric fans:

1. In stop and go traffic, the fan is moving fairly slowly and there's virtually no ram air to help it. On warm days, I watch my temperature gauge creep up, although admittedly the car has never overheated.

2. Going 70mph on open road, the engine is getting a lot of ram air. While it's probably not enough to cool the engine on its own, the mechanical fan is spinning far faster than needed. I think the water pump pulley and harmonic balancer are about the same diameter, which means that on the fan is turning at the same speed as the engine. At 4K(~70mph) that translates into a lot of wasted power along with a tendency to overcool the engine.

Later models of the same car had dual electric fans(NA) or single(rest of the world). The system was fairly primitive as the fans where controlled by a simple on/off switch that activated around 180ºF and the fans only had one speed. None the less, it helped in the two situations I describe above. My car can't be readily adapted to take the factory type electric fans(they moved the radiator support closer to the engine since it didn't have to clear the engine fan and they needed the space for the fans up front. There are aftermarket kits.
 
Originally Posted By: Shannow
I believe that an electric fan is the only one that tells you that your oil viscosity choice is a good one.


lol.gif
 
Originally Posted By: bunnspecial
My one car with a mechanical cooling fan has it directly attached to the water pump(via a V-belt that also drives the alternator). There is no clutch.

I've considered installing electric fans. To my way of thinking, there two deficiencies in mechanical fans that aren't present in electric fans:

1. In stop and go traffic, the fan is moving fairly slowly and there's virtually no ram air to help it. On warm days, I watch my temperature gauge creep up, although admittedly the car has never overheated.

2. Going 70mph on open road, the engine is getting a lot of ram air. While it's probably not enough to cool the engine on its own, the mechanical fan is spinning far faster than needed. I think the water pump pulley and harmonic balancer are about the same diameter, which means that on the fan is turning at the same speed as the engine. At 4K(~70mph) that translates into a lot of wasted power along with a tendency to overcool the engine.

Later models of the same car had dual electric fans(NA) or single(rest of the world). The system was fairly primitive as the fans where controlled by a simple on/off switch that activated around 180ºF and the fans only had one speed. None the less, it helped in the two situations I describe above. My car can't be readily adapted to take the factory type electric fans(they moved the radiator support closer to the engine since it didn't have to clear the engine fan and they needed the space for the fans up front. There are aftermarket kits.


Ram air is usually sufficient to keep an engine cool, unless towing, or driving slow. at 40 MPH you're pushing around 200 cfm through that rad (4ft² surface)
 
In he '1990s I was muckeing around with Cooling Systems (sent some stuff over to Gary Allan).

I had one of these...
UC-torana-1.jpg


Once I found a decent water pump that moved water at idle (the pressed tin "fans" don't move water at idle, not until around 1700RPM would they flow), I put in a bottom hose thermostat, and took the fixed metal fan off.

Covered the upper grill section in duct tape so that the under bumper was the only air in the front, and took the seal strip off the rear of the bonnet, and raised the rear by about 12mm.

That set up enough of a thermosyphon, coupled with the pump that actually moved water, and the lower hose thermostat that I could idle for 10+ minutes without getting too hot.

The lower hose thermostat meant that in winter, I could drive 25km to work with a stone cold radiator, as the block lost enough heat to keep it closed.
 
Originally Posted By: funflyer
Originally Posted By: Olas
I wonder why mechanical fans are still in use with the availability and benefits of electric fans.
Good video though, illustrates how much difference can be made by something you wouldn't normally give a lot of thought to.


Extreme cooling requires extreme CFM, something that no electric fan can do compared to a proper mechanical, engine driven fan.


Wich road cars need more than 3000 cfm? $40 electric fans off eBay do that much. 1000hp cars use electric fans so there really is no need for the parasitic draw you get with a mech. fan.
 
The toughest cooling I deal with is deep sand in 4WD - sometimes with trailer - I'm not moving very fast so the fan does the work. I have done this with both clutch style and dual electric fans (different vehicles) - no issues - but do feel better with dual electric fan set up for the redundancy ...
 
Originally Posted By: bunnspecial
My one car with a mechanical cooling fan has it directly attached to the water pump(via a V-belt that also drives the alternator). There is no clutch.

I've considered installing electric fans. To my way of thinking, there two deficiencies in mechanical fans that aren't present in electric fans:

1. In stop and go traffic, the fan is moving fairly slowly and there's virtually no ram air to help it. On warm days, I watch my temperature gauge creep up, although admittedly the car has never overheated.



Do you hear the "dump truck roar" when you leave a traffic light after this? If no, your fan clutch may be half borked. How about when you cold start it? You're supposed to get a roar for 30 seconds until the clutch loosens up.
 
Originally Posted By: funflyer
Originally Posted By: Olas
I wonder why mechanical fans are still in use with the availability and benefits of electric fans.
Good video though, illustrates how much difference can be made by something you wouldn't normally give a lot of thought to.


Extreme cooling requires extreme CFM, something that no electric fan can do compared to a proper mechanical, engine driven fan.


A Mark VIII can move upwards of 5,000CFM. There are VERY few applications that it cannot keep cool.
 
Originally Posted By: eljefino
Originally Posted By: bunnspecial
My one car with a mechanical cooling fan has it directly attached to the water pump(via a V-belt that also drives the alternator). There is no clutch.

I've considered installing electric fans. To my way of thinking, there two deficiencies in mechanical fans that aren't present in electric fans:

1. In stop and go traffic, the fan is moving fairly slowly and there's virtually no ram air to help it. On warm days, I watch my temperature gauge creep up, although admittedly the car has never overheated.



Do you hear the "dump truck roar" when you leave a traffic light after this? If no, your fan clutch may be half borked. How about when you cold start it? You're supposed to get a roar for 30 seconds until the clutch loosens up.


There is not a fan clutch on this car. The fan is bolted to the water pump pulley, which in turn is driven by a v belt off the front engine pulley.
 
Originally Posted By: Olas
Originally Posted By: funflyer
Originally Posted By: Olas
I wonder why mechanical fans are still in use with the availability and benefits of electric fans.
Good video though, illustrates how much difference can be made by something you wouldn't normally give a lot of thought to.


Extreme cooling requires extreme CFM, something that no electric fan can do compared to a proper mechanical, engine driven fan.


Wich road cars need more than 3000 cfm? $40 electric fans off eBay do that much. 1000hp cars use electric fans so there really is no need for the parasitic draw you get with a mech. fan.


Most cars do just fine using electric fans. Trucks not so much. HD cooling on trucks requires 10000 CFM+ airflow to keep cool.
 
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