i have a 2006 wrangler with a 4.0 L six. I was just wondering if it would be a smart idea to convert to an electric fan. If so what are good fan kits to buy? it also has a K&N intake on it. Any feed back on the fan kit would be much aprreciated
bsi am cursed with the 2.5l engine and automatic transmission. In my case i did notice a slight increase in power. Now, it can almost get out of its' own way.
We'll see if I get a response, and I'll post it if I do.In the 'Jeep 4.0L Myth Busting - True Lies' article, (found here: Jeep 4.0L Myth Busting True Lies - Jp Magazine) Christian Hazel and Pete Trasborg write about replacing the mechanical fan with an electrical fan, and the gain in HP and MPG. The section on the fan swap is now missing. Why? In the article they were in favor of the swap; has that view now changed?
Which im willing to bet was no more than a 5hp increase and in a 3800lb vehicle with an aerodynamic efficiency of a brick your not gonna feel it.fourwheeler.com was the site claiming gains from the fan swap.... and now that part of the article is missing.... ....so I sent JP Magazine a message.... We'll see if I get a response, and I'll post it if I do.
All right, this may ramble.... I am rereading/rethinking and re-researching... and typing as I do....
One thing I keep reading from some of the anti-electric fan side is a misrepresentation of the other argument; that there is a claim that the electric fan is 100% efficient, is free to operate, etc. None of the electric fan backers are stating that. By exaggerating someone else's argument, it's much easier to present your own position as being reasonable, but this kind of statement serves to undermine honest rational debate.
It is hard to pin down a CFM rating on the mechanical fan because it depends on engine RPM AND how locked up the clutch is. I can guarantee you Chrysler has numbers for it, but they are buried in engineering specs/documents. I've seen estimates though in the 6000 CFM range at higher RPM. Really just the size difference should clue you into the fact that mechanical fans can pull more air.I also continue to see statements similar to "electric fans don't cool as well as the TJs factory fan does," but there isn't any temperature readings to back this up. From what I am reading, this is an “old-school” mentality. The newer blade and shroud designs allow for an increased airflow capacity to adequately cool. Also, I can not find what the CFM of the stock fan is; I guess a CFM rating would have to be based on a constant RPM and a direct drive fan doesn't give that option. I would think somewhere there would be a rating “This fan has a CFM of X @ Y RPM (idling speed, cruising speed, etc.)” but I can't find it. My Flex-a-Lite has a 3300 CFM rating, and I know I can feel the air flow difference over my stock mechanical fan. Was my clutch fan operating correctly? I don't know.
I had posed the question, if the energy usage is equal (or worse) between mechanical and electric, than why do the cars being manufactured today all have electric fans? I think freeskier's explanation is solid, but it still left me with some doubts. So I looked into the only vehicle I know/care about, Jeep.
JK's (all?) have electric fans, and I have not seen of any aftermarket manufacturers rushing a "mechanical fan upgrade" to the market to replace them. I searched online; I found one JK owner who did this mod and in the end (the last post anyway,) he ends up running both fans. I didn't quite follow his logic for doing so, best-of-both-worlds scenario I guess, but his write up is worth a read.
Then I looked again at the Jeep's alternator. The argument is that the electrical fan puts a greater load on the alternator and thus on the engine than running the factory clutch fan. This is
If you can see those savings that's great. Personally I'm doing good to put 2000 miles a year on the Jeep.likely false, at best unprovable. There is a mechanical drag (bearing friction) and an electrical drag. The electrical drag will be proportional to the load that the electrical system demands on it. My alternator is rated at 117 amps. My Flex-a-Lite fan has a starting load of < 40 amps, and a running draw of 18 amps. For comparison, my headlights and fog lights have a draw of about 5 amps each, so a 20 amp draw when I'm cruising down the road at night. If my math is correct (18 A X 12.8 V = 230.4 W & 1 HP = 745.69 W), it takes 0.31 HP to operate the electric fan, and you have to consider the fan is not running all the time. The loss of HP is miniscule.
Overall then, there is a greater parasitic loss with mechanical fans than with electrical fans. There just isn't any hard data that suggests otherwise.
The fan is $379.99. Everything I've read on a electric fan conversion says I can reasonably expect a 5% - 10% increase in MPG. If the TJ gets 18 MPG now, a 5% gain will push it to 18.9 MPG, I'll round it to 19 MPG, 10% gain would be 20 MPG. I drove the TJ 15,582 miles last year. Using $3.75 a gallon for gas prices:
@ 18 MPG, I would have used 866 gallons, at a cost of $3,247.50.
@ 19 MPG, I would have used 820 gallons, at a cost of $3,075.00. I would have saved $172.50.
@ 20 MPG, I would have used 780 gallons, at a cost of $2,925.00. I would have saved $322.50.
I can see no reason not to do this, based on my Jeep being a DD. Your cooling needs may be different. This is a well balanced read: Which is Better – an Electric or Belt-driven Fan?