Electric Fans - Who Needs 'Em>

Kid Vette

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Corvette Enthusiast (my favorite Vette mag) has a good article about C2 and C3 cooling systems. One of the things they touched on is electric fans. Here is their take, "What about aftermarket electric fans? Unless you get a really well-engineered dual-fan setup with a full shroud that covers the entire face of the radiator core (with pressure-relief flaps for added ram airflow at highway speed), they're a poor substitute for the factory fan setup, they don't move anywhere near the volume of air the fan/clutch system does, and they place a major electrical draw (30-40 amps) on the system at the worst time, when the alternator is at its lowest speed. The typical single round aftermarket fans that attach directly to the radiator core only draw air through the portion of the core that's enclosed within the diameter of the fan blades. the other 50 per cent of the face of the radiator core gets no airflow at all. The factory shroud ensures that air is drawn through every square inch of the core, all the way to the corners."

This is something I have believed for a long time. Electric fans aren't worth all the expense of the conversion. So why is everybody going with electric fans?

By the way, you should read the whole article - lots of good stuff.
 
First thing that comes to my mind is " why are there no modern production cars with a belt driven fan nowadays?"

I do not have a cooling issue with the stock setup and a Aluminum radiator but would prefer electric fans, preferably the dual setup from a '93-02 f-body donor, that hardware seems to fit pretty well without major modification or fabrication (and it's cheap).

Electric fans can be programmed to turn on and off at specific temperatures and there is no belt that can slip or break. I do not like the idea of that stock fan spinning at 5-6000 rpm either...

just my2c.....
 
The electrical draw part is certainly true, though many have suggested using a higher output alternator when you put dual fans in.
 
I have no problems with engine cooling with my engine driven fan. I have an aluminum rad now, but had no problems with the copper unit either.

There is one reason why I'd put in an electric fan. Spreader Bars don't fit with a BB stock fan.
 
First thing that comes to my mind is " why are there no modern production cars with a belt driven fan nowadays?"Huh?

I do not have a cooling issue with the stock setup and a Aluminum radiator but would prefer electric fans, preferably the dual setup from a '93-02 f-body donor, that hardware seems to fit pretty well without major modification or fabrication (and it's cheap).

Electric fans can be programmed to turn on and off at specific temperatures and there is no belt that can slip or break. I do not like the idea of that stock fan spinning at 5-6000 rpm either...

just my2c.....

Bigger pulley:pprrtt:
 

So are there any cars with belt driven fans manufactured after 1990 ??

I'm not saying the stock system is all that bad but if electric fans were not better then why is everybody using them ? Like I said, I don't have a cooling problem but if I did I'd rather spend the money on a electric fan setup than on a new fan/clutch/seals a.s.o.
 
This is something I have believed for a long time. Electric fans aren't worth all the expense of the conversion. So why is everybody going with electric fans?
.

i agree.

Well, its harder to cut your finger off in an electric fan. That might have weighed heavily in auto manuf considerations when putting electric fans in all new cars.
 

So are there any cars with belt driven fans manufactured after 1990 ??

I'm not saying the stock system is all that bad but if electric fans were not better then why is everybody using them ? Like I said, I don't have a cooling problem but if I did I'd rather spend the money on a electric fan setup than on a new fan/clutch/seals a.s.o.

My 92 Caddy and the 03 Silverado both have mechanical fans. Matter of fact, I have zero cars with electric fans.;)
 
I've got the same feeling about it. Only problem is, my engine can get to 7500 rpm which seems way to much for the stock fan to hold up.

Anyway, i'm thinking the factory put in the electric fans because of fuel concerns and because of the limited space in today's cars.
 
FACTORY puts in electric fans because in 90% of today's CARS on the road, the freeking engine is SIDEWAYS......FWD, remember guys???

aside from that remark, electric fans are the way to go, just upp the alt a tad, I use a 17SI unit like out of a '79 Eldo with RWDefogger....108 amps and it's a plug in swap....slightly larger diameter is all.....

It also runs the DPFI without problems also....

and the C4 a/c blower.....

IF I install the stereo in there, I maybe want to use a 9 volt battery to run it though.....


:3rd::quote:
 
FACTORY puts in electric fans because in 90% of today's CARS on the road, the freeking engine is SIDEWAYS......FWD, remember guys???

Bingo. Engineering solution, nothing more. Might help with A/C at idle too.
 
There are also advantages to electric fans apart from the obvious. Ever thought of engine warm up? Without that lawnmower blade whipping around there the engine reaches operating temperature a lot quicker.

Just like Karsten says, the ability to thermostatically control them is a great benefit.

Also, if there is jsut a hint of imbalance in the fan the water pump will leak much sooner also.

Fact is, you won't need the fan most of the time if your cooling system is in proper working condition. If you want to use an electric fan in the original shroud, consider installing an early C4 fa. This way it pullsthrough just as much core area as the stock fan:

2483d64edb05de.jpg

2483d64ee48ffa.jpg

2483d64eec864e.jpg


If not, you can always fabricate a shoud. It's pretty easy with fiberglass, a little more involving with aluminium. You can buy fans with shrouds also, like the FlexaLite ones, they won't cover all of the core but will cover a large area and moving the fan towards the inlet side will help getting the largest temperature differential most efficient cooling)

i never cared for mech fans. If you have cooling issues, get a bigger radiator and/or increase airflow into the radiator. if you have cooling issues in stop and go traffic, add more fan area.
 
I agree with you TT :thumbs: The Dual Spal electric fans with a BeCool/DeWitts radiator has been one of the top upgrades I have made on RamJet.




Unless you get a really well-engineered dual-fan setup with a full shroud that covers the entire face of the radiator core (with pressure-relief flaps for added ram airflow at highway speed), they're a poor substitute for the factory fan setup,

This is something I have believed for a long time. Electric fans aren't worth all the expense of the conversion. So why is everybody going with electric fans?

Kid, how did you interpret the above statement into ---"Electric fans aren't worth it"?

Bullshark
 
There are also advantages to electric fans apart from the obvious. Ever thought of engine warm up? Without that lawnmower blade whipping around there the engine reaches operating temperature a lot quicker.

Just like Karsten says, the ability to thermostatically control them is a great benefit.

Also, if there is jsut a hint of imbalance in the fan the water pump will leak much sooner also.

Fact is, you won't need the fan most of the time if your cooling system is in proper working condition. If you want to use an electric fan in the original shroud, consider installing an early C4 fa. This way it pullsthrough just as much core area as the stock fan:

.


I'm going to disagree with the master on all counts.

1. The thermostat controlls engine temp. The fact that the fan pushes some air past the block causes negligable cooling.

2. The electric fan allows the mass of coolant in the radiator to get hotter by not running all the time. This provides a significant difference in thermal reserve that may be needed at any time for a high speed run or other high load condition where the engine creates a lot of heat. The thermostat will open only to find the incoming coolant is hotter with less effect on cooling.

3. With good H/D bearings a water pump can tolerate imbalance. The imbalance is not continually present at any point on the shaft because of fan clutch slippage.

4. The C3 due to its small frontal area and sloped radiator and relatively poor design does not get as much forced air due to speed than most other autos. It really helps to have a mech fan running all the time creating a very beneficial negative pressure behind the radiator.

There are good reasons NOT to change.
 
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Actually the thermostat does NOT control engine temp, it controls the MINIMUM operating temp. Once the stat is open, the capacity of your cooling system controls the temperature, too little and the temps will climb. More than enough and it'll drop to where the stat closes again and as a result will somewhat control the temp. The stat closing is ommonly seen on transverse mounted engines where the oncoming air also directly cools the engine block on it's "side", especialy on small engined econoboxes. Some never even get hot enough that they have additional electric interior heaters (usually diesels) because the cooling system is inadequate to heat the interior.

The frontal area, the radiator gets air from underneath. The biggest problem is not the frontal area, it's the sloped radiator. That's why the seals are so important, missing seals resutl in air flow not going through the core but past it and over it.

You really do not need a large opening to supply enough cool air to a radiator. What's important to have enough flow through the core and this means that ducting to but also from is important. It's the from area where the stock shroud comes in.

Also, there are a lot of components that people put on their cars that will deteriorate your cooling system. One of those most common ones are those ugly stainless ribbed for her pleasure hoses. They look good (well to some, not to me) but they really don't do your cooling system a lot of good. A proper smooth bore hose and/or a ribbed on the outside against collapsing (especially for the lower one, or use a spring) are a much better idea.

Good reasons to change are also, it unclutters the engine compartment, you have room for other stuff there. I'll never use a mech fan again.

Also AC condensators greatly reduce radiator effectiveness, I don't run AC on anythig
 
it controls the MINIMUM operating temp. .

therefore it controls temperature. :D You're playing with words. We all know the STEADY STATE max operating temp is controlled by the system design parameters and ambient temperature.

But, you are making my point for me.

The point is, you have less control over temperature with no thermal reserve. You want fans pulling air past the radiator at all times to keep the coolant in the radiator as low as possible at all times so the engine thermostat will have more control over the maximum operating temperature.

Let me spell it out. I'll use an extreme example. If the electric fans kick off until the radiator coolant temp hits 185. Then the engine thermostat opens at 190 the delta T is only 5 degrees. You then immediately make a quick blast up a mountain road. What do you think the system temp is gonna do. Probably hit 230.

With the mechanical fan turning all the time the radiator coolant temp is lower say 140. The engine thermostat opens at 190 so the delta T is 50 degrees. Now you make the same quick blast up a mountain road. You have a lot of cooling capacity there due to the large mass of cool coolant in the radiator. The max temp probably will not exceed 190.

And at speed, who is going to argue that a negative pressure behind the radiator to increase the delta P resulting in more flow through the radiator is a bad thing.?

BTW, When i owned my Regal Grand National i bypassed the electric fan thermostat so it would run all the time when the key is on. Yea, the fan needed brushes much sooner than it would have but that's a small price to pay to keep engine temps from spiking.
 
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I agree with you TT :thumbs: The Dual Spal electric fans with a BeCool/DeWitts radiator has been one of the top upgrades I have made on RamJet.




Unless you get a really well-engineered dual-fan setup with a full shroud that covers the entire face of the radiator core (with pressure-relief flaps for added ram airflow at highway speed), they're a poor substitute for the factory fan setup,

This is something I have believed for a long time. Electric fans aren't worth all the expense of the conversion. So why is everybody going with electric fans?

Kid, how did you interpret the above statement into ---"Electric fans aren't worth it"?

Bullshark
The fact that I've never seen an installation that meets the criteria of a "really well engineered dual-fan setup" leads me to the statement that "Electric fans aren't worth it".

Here is a pic your setup from DeWitts web site.

sp031.jpg


The shroud only covers about 80% of the radiator surface. That would make it "a poor substitute for the factory fan setup".

I'm enjoying all the discussion in this thread. More intelligent discussion here in one thread than in ALL the threads in a month elsewhere. :thumbs:
 
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