Fan What to do

i just put a flex fan on my car that pulls more air than my stock fan with HD clutch on it....my stock fan had been chewed up because both motor mounts were shot when i bought the car. the flex fan pulls more air, but the car doesnt run any cooler. im thinking about a new radiator now

I guess there's always going to be those who prefer mech, those who prefer electric. There's tradeoffs for each.

I've heard the argument that mech pulls "way more" CFM than any electric, but I'd really like to see some figures before I believe that. I don't know how to measure it myself, but I can tell you when I had my foot hanging out the door at idle, with the mech. fan I could feel it blowing air on me when the fan clutch was engaged (only when I rev'd it), and with the taurus fan jumpered to full speed I feel pretty much the same amount of air passing, except it's a constant flow of tons of air, instead of just when I rev it up like with the mech. fan.

The DCC controller costs about $110-120 bucks (can't remember exactly,) and the Taurus fan costs anywhere from 20-100 depending on what junk yard you find. It pulls I believe 4000cfm on the high speed setting, and covers about 80% of the rad, and frankly I don't think it matters. The DCC unit measures the coolant temp by a thermal probe placed at the very bottom of the rad by the outlet, not at the top like other controllers. With another controller, it would sense the temperature of the coolant flowing in, kick the fan on, etc. With the DCC unit, it allows the radiator to do it's job first by disapating all the heat it can, then measures to decide how much cooler the coolant needs to become. Then, it turns the fan on. There's no loss of cooling properties IMO just because it doesn't cover the whole radiator. The radiator dissapates the heat, the fan only aids in the dissapation process. Frankly, that 20% of the radiator that is exposed, is probably HELPING because it's straight ram air through that part, no shroud blocking it, nothing.

Fan coverage is an issue. The Black Magic fan has lots of power, pulls lots of air but only covers about 17" of the radiator. The ramcharger covers enough in width, but isn't as tall so it dosen't cover the radiator fully either. It is better to have less air pulling from a wider area than just one spot blown hard. At a certian point, effeciency of the heat transfer decreases. I have a Black Magic fan which did well on the stock radiator and the 3 core stock replacment, but since I just got a AFCO 31" wide unit, it hardly covers half of the radiator. I am thinking of getting the Flex-a-lite Dual 13.5" fan system. It is made for GM Trucks, but can be used universally with any radiator with a core of 27.5" or more, which would fit my radiator perfectly. If all else fails, I have a GM truck as well. GM has started switching thier trucks 05+ with electric fans.

90mustangGT said:

Fan coverage is an issue. The Black Magic fan has lots of power, pulls lots of air but only covers about 17" of the radiator. The ramcharger covers enough in width, but isn't as tall so it dosen't cover the radiator fully either. It is better to have less air pulling from a wider area than just one spot blown hard. At a certian point, effeciency of the heat transfer decreases. I have a Black Magic fan which did well on the stock radiator and the 3 core stock replacment, but since I just got a AFCO 31" wide unit, it hardly covers half of the radiator. I am thinking of getting the Flex-a-lite Dual 13.5" fan system. It is made for GM Trucks, but can be used universally with any radiator with a core of 27.5" or more, which would fit my radiator perfectly. If all else fails, I have a GM truck as well. GM has started switching thier trucks 05+ with electric fans.

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I agree completely. People get all caught up in CFM, and totally disregard surface area most times. The ramcharger fan supposedly only pulls 2340CFM, but I've seen plenty of people with the Griffin/RC combo have no issues with cooling on blown and A/C'ed cars. I was just trying to figure out how I want to mount the RC fan to my Griffin, and you are right, it doesn't cover the 31" Griffin from top to bottom, but it's pretty close. It's about 16" tall, so it only leaves about an inch and half on the top and bottom assuming it's centered. It covers completely from left to right, and actually needs to be trimmed a bit. In my opinion, in most cases, you will get better results with a dual fan that flows less air than a super high CFM single fan. I also like the low draw it has even on high, and the fact you can control each fan independently if you wanted. From off to high it will pull about 31A for a second, then drop to ~24A continuous. I prefer that over something like the SN95 or MKVII fan which pull upwards of 50A.

Best of all, it's only $80...

The plastic fans crack -- but (after four 5.0 cars) I have yet to read about (or see) one actually come apart. As to electrics -- they have their place but I am one who thinks that they don't work as well, and you have to increase radiator size if you want the benefits of getting rid of the HP loss from a mechanical fan.

First, you are changing a factory-engineered setup for your own design, which includes many variables (what fan; what controller; what settings; etc.). Also, you most likely will not have a fan shroud, reducing the fan's effective area. Plus, most (if not all) aftermarket modified setups only account for temp, but don't include road speed. Factory electrics turn off at speeds above 40, because road speed puts more air through than the fan. But if the fan is still trying to work, it is counterproductive and could actually set up a blockage to airflow at that point, reducing cooling.

My real world experience comes from changing a 94 Chevy Caprice with tow package cooling (which means a mechanical fan with electric secondary/backup) to the dual electrics found on Impala SS's. Either way this is a serious cooling setup, but there is no question that the mechanical cooled better. Chevy rates the mechanical fan setup for an additional 5000 lbs towing capacity, and I saw the cooling fall off when I went with the factory electrics, despite going to a 160 thermostat and reprogramming the computer to turn on the fans at 180. There just wasn't that consistency of cooling, and I found my eye wandering to the temp gauge a lot. Even though the 2 16" fans were rated at 100 and 240 watts respectively, I saw more temp creep in traffic, which meant less airflow.

But there is no question that there was a huge difference in seat-of-the-pants performance feel. Going electric made that car feel like I cut the anchor chain with an axe. The car instantly felt 500 lbs. lighter. However, it ran hotter and I ultimately went with a bigass Becool aluminum radiator to get it back it where it had been in terms of cooling performance in traffic with 100 degree Los Angeles temps.

Finally, I have found that factory Ford mechanical fan clutches work best. Aftermarket clutches are universally too tight, which improves cooling, but hurts HP. You really can feel the difference, so unless you think the rest of your cooling system is not up to par and needs the extra help, spend the extra dough and get a genuine Ford clutch. They freewheel and lock up like they are supposed to.

Sam -

I've seen this argument before, but I disagree. The argument is that since it came from the factory, it's obviously the best design. If mechanical fans are so good, how come you almost never see them in cars anymore? I think at the time the fox Mustangs were designed, a mechanical fan probably made more sense, and was cheaper. That does not mean that an aftermarket fan is going to be worse if you set it up right, and get the right one for your application.

I do agree on there being no real reason to have the fan on above a certain speed, which is one reason why I am setting mine up with a custom dual switch setup, so I can control the fan as needed, and not rely on a temperature based controller.

I think both mechanical and electric have their positives and negatives, but I don't really think you can make a blanket statement about one being better than the other in all cases. There are simply too many variables.

Also, I've seen you say before that most electric don't come with shrouds...this is simply false. All the most common aftermarket electric fans for the 5.0 Mustang come with integrated shrouds. Of course they aren't as large as the one for a mechanical fan, they simply don't need to be.

Just my .02...

SamSnyder said:

you have to increase radiator size if you want the benefits of getting rid of the HP loss from a mechanical fan.

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Not true. I have the stock radiator with my Taurus fan setup, and I have already experienced cooler temperatures idling in traffic here in Tucson.

SamSnyder said:

First, you are changing a factory-engineered setup for your own design, which includes many variables (what fan; what controller; what settings; etc.). Also, you most likely will not have a fan shroud, reducing the fan's effective area.

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Also not true. The Taurus fan and nearly every aftermarket electric fan includes some sort of shroud. And in any case, the fact that my fan only covers 80% is meaningless. The fan can easily cool the passing coolant with the 80% it has to work with, and it barely runs the way it is.

SamSnyder said:

Plus, most (if not all) aftermarket modified setups only account for temp, but don't include road speed. Factory electrics turn off at speeds above 40

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Neither does an OEM electric fan. It has nothing to do with speed, whether the fan comes on or not all depends on the temperature of the coolant passing wherever the sensor is mounted. Speeds above 35 or so usually don't require the fan, because of the passing air, not because of a speed sensor.

Sam's point was that OEM electronics shut fans off once at a given speed (35-50 MPH generally, depending upon the car). In said cars, once the VSS tells the puter that this threshold speed has been met, even if the car is running hot (where the fan would be on, if at a lower speed or idling), and the fan shuts down.

As said, at speed, the fan is an impediment. So this is a neat feature, I think.

We are seeing that people have varying opinions. Personally, I find that I can agree (or see the vantage point) of about each person in here. I still prefer mech set ups because they seldom just take a powder all at once, like can happen with an electrical set-up.

But really elec fans and mech fans work pretty well, so people can support their one pretty equally. When considering performance, tractability, etc, one is not really better in any absolute way than another - it is personal preference. So the debate continues.

Agreed on the shutting off at speed Hissin (and Sam). That is one reason why I chose to go with a switch setup so I could determine when they will be running. I know everyone loves the DCC unit, and for good reason, but I personally prefer a switch setup for the ultimate in control.

In fact, it's hard to get much advice on setting up a custom electric fan setup without everyone telling you to just forget everything else and get a DCC...I finally gave up.

I say go electric I really like my electric fan cools real good.

When it's all said and done, an electric when properly setup is very reliable, and does reduce on the parasitic load on the motor.