I have read many of the electric fan conversions, good info on that. But the question I have is that I have seen some bolt on performance fans that look like stock only smaller (metal fins) and claim 3000 cfm, they are about $45 at the parts store here. Can anyone tell me if these free up the motor at all or is this pretty much the same as stock? Worth doing, or is this an electric fan or nothing type mod?

 

If I'm not mistaken, I believe you are talking about a flex-fan? Yes it will free up a couple horses, but at the cost of noise. Think your stock clutch fan is loud on a hot day? Wait till you spin one of these puppies up on any day.

Performance increase will be negligible. You are still using the engine to spin it.

Electric? Best bet IMHO. Takes even fewer horses to run one (Puts the load on the alternator that's already spinning), Isn't on all the time, Engine will warm up faster on cold mornings. Water pump bearings will last longer, blahblahblah.

Only downside to electric is it does cost a bit more to get set up correctly. Don't go super-cheap when choosing a controller for it.

Going with an electric fan is on my list of things to do for my '06 (3.7L). I know the truck will get a bit more pep. "Should" also get me another 1.5-2 MPG.

 

Any engine driven fan is going to use engine HP. Visible blade size doesn't tell you how much HP is going to be used, you need to look at the cfm at some rpm and make a comparison on that - the more aggressive the fan, the more HP it will use.

For fan upgrades, my preference is to use an aggressive e-fan and the one of my choice is a 2 speed configuration from a Ford Taurus. These fans can be obtained very cheap from an auto salvage yard and with a bit of DIY on the shroud, you can fit it to the Dakota. I use ABS sheet (this matches the material of the shroud that the fan already comes in, so the idea is to modify the old, not create all brand new), self tapping screws, and a heat gun for this purpose - 1/8" for covering sections and 1" for strength, rigidity, and blocks where you can drill and use screws to pull everything together. The heat gun is to heat the ABS up to the point where it becomes pliable, then you form it and let it cool to hold it's shape. I also use ABS solvent in all the joint areas to add strength. For fan control, I prefer using a Pulse Width Modulation (PWM) control unit vs. a relay system, but either will work if done right, the PWM will give more versatility and use less power and when you add up all the parts, both control systems come to about the same cost - relays will be somewhat cheaper, but you won't be able to use the OEM temp sensor and so you'd end up needing a new sensor per fan speed and the plumbing parts that you'd need to get the sensors into the engine coolant. If you do go for something like the Taurus, keep in mind that it uses a LOT of amps to start.

 

I would advise against the Taurus fan. The only way for it to work is to wire it straight to the battery without a fuse. In some cases it pulls 80+ amps on startup! In one case, I read how a Mark VIII fan (similar to the Taurus's) pulled over 100A on startup.

They are more expensive, but there are many fans that blow just as much as the high amperage Ford fans and pull far less.

 

Since I have the HHR fan, I can tell you guys that it really is a nice fit and flows more than enough for our radiator size. It works well at half speed too, as I have the SPAL dual fan controller. On the 3.7L, HP, torque, and fuel mileage increases are noticeable.

 

The HHR fan is a pretty good upgrade for many vehicles such as the Dakota. It delivers pretty close to 3000 cfm (if memory serves me correctly) and this is equivalent to a lot of third party fans. This fan is very cheap at an auto junk yard, single speed, and draws under 20 amps. PWM units such as the SPAL (keep in mind that this one isn't manufactured anymore but can still be found for sale - if you buy one, it won't have a manufacturer's warranty) can easily be incorporated into a multi-speed cooling solution. If a simple,single speed solution is adequate, a single relay and a thermal sensor can be used to turn this on/off.

I'm a "fan" of the Ford Taurus 2 speed fan. This one & it's close cousin the Mark 8 (this one comes in single and dual speeds) do use a lot more amperage and aren't as easy to integrate with a lot of the available controllers as the lower power units (lower power usually means lower cfm). There are quite a few articles & videos on the internet giving the Ford Fan specs - the main thing about these fans is that they move a LOT of air, generally rated around 4500 cfm at high speed, and around the 3000 cfm mark for the low speed operation. This performance is really good for more extreme environment such as hauling, off road, and a lot of slow speed operation in hot weather. Both of these fans have a large in-rush current, but this levels off to the "running level" in a fraction of a second - my tests showed around 65 amps in-rush, and around 32 for high speed running. With these numbers, the average relay or PWM controller just won't last. For relay control, I use a combination of relays and 100% duty cycle solenoids (and back EMF and contact arc protection - this is often ignored by many implementers). For PWM control, I would recommend a Painless unit - this is the only one I found that was easily available on-line and is able to handle the amperage. I use a solid state controller of my own creation, and anyone with some electronics and/or robotics background could do the same. When implementing either controller solution, keep in mind that the main line to the controller should contain a fuseable link that can handle that current level. I've added a separate power distribution box to my truck. This box is connected directly to the battery and gives me a "headache free" solution when adding anything to the truck that I want to bypass computer scrutiny.

 

How a fan can increase fuel mileage by it self?

 

The mechanical fan takes effort (power) for the engine to spin it. Removing it and adding an electric fan gives you some slight power/mileage gains, albeit only in town (on the highway, the clutch slips enough on the fan that it's power drain is almost negligible).

 

Got it guys, thanks for the heads up, looks like E-fan or nothing.