Jeep I6(242) E-Fan Swap - Fuel Economy, Hypermiling, EcoModding News and Forum

DifferentPointofView · 05-21-2008, 01:26 PM

Okay, so I didn't do this myself. But I did find out a DIY Post on a Jeep forum to swap out the mechanical fan for an electric fan.

The fan operates on an on-off-on switch, up if for high, middle is off, and down is low fan speed.

Not only does this benefit in quicker warm-ups, but since your mech. fan runs off belt speed, if you run low rpm's at highway speeds (i do) your Mech. fan isn't cooling off the engine efficiently if your going up hills and generating heat, but the belt speed is the same. This isn't much of a problem in the ZJ's, but for the TJ's and YJ's, their cooling system could use a bit more work.

With a full grille block in the summer, the temps can start to rise a bit, though I haven't seen temps over 200, could use a bit more cooling (oil temps are high and I'm getting low oil pressure from leakage). So if you are out wheeling or rock-crawling, and your giving your engine hell but the rpm's are in the low range, you need a cooling fan that can run on high, because your belt is making your mech. fan run slow. Well here's the DIY for an E-fan swap. It involves taking one out of a 3.8L in a Ford Taurus/sable/lincoln etc. Two bolts and you cut the wires.

http://www.jeepforum.com/forum/showt...ghlight=taurus

SVOboy · 05-21-2008, 06:33 PM

Nice find!

Smoove · 05-21-2008, 09:33 PM

I did the Taurus fan swap, and it required a ton of trimming to fit in the space alloted. It required a ton of power when it would start-up, and fried my DC controls controller.

I have been using a perma-cool 19115 16" fan and flex-a-lite variable speed controller for 6 relatively trouble free years.

This reminds me, I gotta put that Taurus fan on fleabay this summer, it has been in my in-laws basement since 2005!

meemooer · 05-21-2008, 11:32 PM

i did this last year before a weekend towing trip. I've towed the car to be towed back before, and i could tell it was one hellava difference. I gained i think 1-2mpg at the time. The biggest advantage was working under the hood. No worry about getting my hand in a blade, plus way more room, and changing the belt was so much easier.
ohh and i bought a kit for like $140 with a controller, wiring, fan, and whatnot, from a ranger online store. I'm happy

Red · 05-22-2008, 02:20 AM

About a year ago or so I did the swap on my TJ. I didn't really notice a major change in MPG or power. It was a cool gizmo though, but it does have a tendency to die when mudding. It did keep the coolant temps nearly dead on 207F no matter what.

Smoove, how'd you kill you DC Controller? Mine didn't suck that much power when it did a slow start up

Smoove · 05-22-2008, 10:36 AM

Quote:

Originally Posted by Red

Smoove, how'd you kill you DC Controller? Mine didn't suck that much power when it did a slow start up

I loved it, and I would have bought another one but they are made in batches - and my wait time was around 5 months, which would have meant November wrenching.

Even on the slow start it would chug power, dimming the lights and causing an idle surge even though the controller was enabling the low speed only. I don't recall the exact numbers, but it was high. Since then fan only came on at traffic lights I eventually set up a manual override, which allowed me to kill the 12v signal to the controller if the light was about to change and throw the high side on as soon as I got moving.

DifferentPointofView · 05-22-2008, 02:14 PM

How much power does it draw? I run a 2400wPeak stereo with no problem unless i wanna hit high db's. By then my ceiling upholstery is falling apart and my mirror falls down and it points to the floor. and It causes my ears to ring badly. I don't know how much power a fan could draw.

adam728 · 05-22-2008, 02:46 PM

I believe the Taurus fan can draw as high as 60 amps, and this is a constant load.

A stereo is rarely a constant load, unless you are just listening to sin waves at peak power (like doing burps at a competition). An amplifier that draws 100 amps at full tilt might only be hitting that number for 5% of the time during a song.

Also, 2400 watt peak means next to nothing, RMS wattage is what is meaningful. Lower-end companies like to use peak "if struck by lighting" wattages, where a "1000 watt" amp may only put out 100 watts rms. This is why something like my old 400x1 Rockford (bench tested 744 rms) would blow the doors off my friend's 900x1 Lanzar when we swapped it in. That 900 watt Lanzar was peak power, rms was 250 or 300 if I remember correctly, and even then, possibly over rated.

DifferentPointofView · 05-22-2008, 03:02 PM

I know about peak and continuous. It's rated at 1200RMS. I did it with a competition bass test. It's hooked up to 2 4ohm subs wired parallel. Its drawing around 1200wRMS at 14-14.4 volts.

I was just saying, if a burst at 2400 watts dims the lights, I was wondering how much power a fan was actually drawing.

adam728 · 05-22-2008, 03:25 PM

We could also get into a lot of things with impedence rise based on the box size/design, specific subwoofer model, wiring configuration, frequency being played, etc, and find that you might only be putting a few hundred watts RMS into them and dimming the lights. Power thru a resistive load for rating purposes comes out much different than power thru a reactive load (speaker). A sub setup might be rated at 2 ohms, but you could throw it in a ported box, play a 50 or 60 hz sine wave and find that the amplifier is seeing something like a 12 ohm load. So that 1200 rms really only cranks 200 rms at that point. Because of box tuning, resonant frequency of the car, cancelation issues, etc, it might be louded at that particular frequency, even though a lower sine wave my put three times a much power into the subs.

If putting out a real-world-in-car wattage of even 600 rms, an 80% efficient (class D) amp at 14.0 volts will only draw 54 amps.

My long winded pointless point is that your stereo probably is not drawing nearly the power you think it is, yet can dim lights. So a large electric fan dimming lights on startup is not that surprising.

Smoove · 05-23-2008, 12:51 AM

I was probably running close to 1000w myself, with no problems on the stock 90a alternator. I built my system for SPL, and with the standard Jeep a/c (which means it never worked), I typically drive windows down and sunroof open, 75mph and the stereo on. I am also running 85w driving lights through a harness. Nothing ever gave me grief, until I used the fan. I believe it drew 80a on startup, 60a continuous draw, but I am not 100% on those numbers. Even with a 160a Ohio Generators amp it was a little worrisome.

The perma-cool/flex-a-lite combo doesn't cool as well, it does the job but scared me once or twice, but it is much more trouble free.

DifferentPointofView · 05-23-2008, 01:25 PM

I just realized I typed 2400w stereo *doh!* I meant 2400w (1200wRMS) sound system.

Nerys · 06-02-2008, 03:41 AM

I see this 3 fan fully sealed ball bearing setup on ebay for the cherokee for $275 was considering it. Claims it only draws 5.8amps.

I am also thinking about electrifying everything else. Gearing an electric motor the the power steering and setting it to say only turn on when below 40mph

Electric Water pump.

that would eliminate all belted devices except the alternator and the compressor. I was also thinking of disconnecting the alternator and adding some batteries but keeping the alternator installed as a "just in case" and "plug in" to recharge.

I am also thinking peltier coolers. Route the coolant to a small aluminum tank at the bottom install some peltier coolers on the tank with some beefy fins right in the airstream. I am wondering if the cooling verse amp draw would be better than the fans etc.. (gonna have to meter a peltier and see how much power they draw)

Lots of ideas. Just need time and money to do them.

FINALLY got the jeep running again. Had a bad Harmonic Balancer Repalced No fix bad fuel pump replaced no joy still ran like crap.

Was about to do full computer sensor swap from the donor vehicle and mechanic bumped the cat. We both heard it and went hmmm. Maybe it was choking itself. Disconnecting the exhaust RAN like a champ!! so I grabbed the entire exhaust from the other jeep (cat back no header pipe rusted) Good news the cat is 1/3 the size of the other one (same year vehicles too!! odd) bad news this means the header pipe will not REACH the cat :-) I will either have to add a chunk of pipe inline there is move it forward if the hangers will permit it and extend the tail pipe. We are going to do this tuesday.

At that point my baby should be drivable! (452,000 miles on the engine we just took out!!!) I used to clock 50 to 60 thousand miles a year back then :-)

My jeep is finally coming back to life!! :-) I can't wait!

rgathright · 08-12-2008, 09:46 PM

Here is a list of things I did:

1) Electric Fan, go with high CFM! The engine will overheat in the summer with AC on.
2) Remove front driveshaft. Simply get a crecent wrench and undo the bolts holding the front shaft in place. You will notice a reduction in the amount of pedal you need @ 75Mph+. I can post pictures if you do not believe me... this mod really works!
3) Disconnect alternator cables and run in Hybrid mode. The Jeep TJ can travel 30 miles with four restarts in this mode on the stock battery. I bought a 12 amp battery charger at the local hardware store and recharge with a quick disconnect cable everynight.

Here are some pics:

Here is a 90% efficient power supply that I rebuilt/upgraded for this use.

I now get 22 MPG on a lifted 33" tire TJ.

Visit my blogs on myspace for more info. http://www.myspace.com/reubengathright

Red · 08-12-2008, 09:57 PM

Welcome to EM rgathright

Bad habit from JF, but is your MPG calculated with the right speedo gear?

rgathright · 08-12-2008, 10:16 PM

I know when I'm going 70 its actually 75.

I do not want to fix it because it is Roundtree Dodge's fault, they sold it to me that way.

Nerys · 08-12-2008, 10:32 PM

Is your 22mpg "corrected" for your odomoter value adjustment? If your speedo is off almost 99% certain your odo is off as well by the same percentage :-)

My jeep has auto hubs and select track (cherokee XJ) I will verify but my front drive shaft should not be spinning at all when I am in 2wheel mode. Is this specific to TJ's ?

Right now mods mean nothing to me as I am netting a measily 18-19mpg (bad O2 Sensor grr those things are expensive and while I have in fact spent TWICE the cost of an O2 sensor in extra gas sadly the O2 Sensor seller will not take "payments" :-) hehe

I am curious about the alt disconnect. I run the air (its just too hot not too) so I am not sure if I could make my commute and the second half is at night. While I do not need the air at night lately I do need the lights.

Also what has it done to your battery in wear and tear? IE have you factored the cost of sooner battery replacement in?

I imagine your largest savings will be the front shaft disconnect if your is always spinning otherwise. I guess I am going to have to check mine and see if it spins.

Smoove · 08-13-2008, 12:41 AM

I have recently ditched the electric fan setup, the VSC started giving me grief (staying on constantly, even when the car was off or not turning on at all) and with my time in my ZJ coming near an end I made the call to go back to stock. I lost .5 mpg.

I used to remove my front driveshaft during the summers (01 to 05), especially for long trips, and I would only gain a few tenths improvement at best. I attribute most drastic driveshaft removal mileage increases from the better summer gas and not letting the car idle to warm up. Also according to my g-tech my 0-60 and 1/4 mile times were not affected. I don't mind crawling under the rig for an improvement, but I can't justify this one.

Hybrid mode sounds interesting in a not-for-me kind of way, its still cool that someone is trying new things. As a city guy I can't plug in every night (or ever), plus I like my electrical goodies.