paker

This is what I know from searching this forum and others.

Clutch fan: engine power ----> fan movement
Electric fan: engine power -----> electricity -----> fan movement.
Electric fan has one more step and is less efficient. But electric fan can be stopped entirely when natural cooling from vehicle movement is sufficient. This makes electric fan come out ahead in energy saving and gas mileage.

I looked into the fan control of my Chevy. Car computer closes fan relay when vehicle speed is less than 37 mph and coolant temperature near thermostat exceeds 220 F.

Starting a DC fan motor has issues. My Chevy has 2 fans. In low cooling, 2 fans are put in series. Each fan sees 6V. In high cooling, each fan runs at full speed (12V). High cooling conditions are AC ON and temperature higher than 300 (? exact number not sure). Neither fan is directly pushed into high speed from 0 rpm.

Here are my questions about aftermarket control (including junkyard parts):
1. Is fan on/off tied to both vehicle speed and coolant temperature?
2. Does fan ever go from 0 rpm to high? (big no)
3. Does fan control sense AC ON?
4. (overlapping question) When does fan switch from 0 RPM > LOW > HIGH?

Thank you.

mbb

electric fans can also run higher rpm,not restricted to engine low rpm, hence lighter lower pitch blades and small direct driven bearings, for more efficient air movement...less drag .

Jbrew

So have you guys figured it out truly ? Over the years I hear guys say it's 10 hp increase along with better economy. I thought about it once when a I had a sticky clutch fan. Man that was a drag, loud as hell. But ended up finding a Motorcraft replacement that cured the problem.

There's just been a lot of ridicule or skepticism trading one power robber for another.

white89gt

Yeah, I have heard all of that riff raff too, Brewster. I honestly didn't feel anything one way or the other in freeing up horsepower on my car. What I did notice though was that my car was no longer quickly rising in temp every time I gave it the juice (and no more noisy fan). I did add a 130 amp alternator to it from a 2001 V6 Mustang so I had enough amperage to run it though (as well as the stereo). No way would the stock 85 amp'r run that pig. The other thing that I like is that in the winter, an electric fan will make your heat come on quicker, LOL. My Escape has heat pretty quick... I would assume that is partially due to the electric fan.

So I am pretty excited to get this Cougar fan on my truck. It never spikes or anything like that, but to me, the benefits were enough for me to want to do the project again on Truck Norris.

paker

Thank you, mbb. I haven't read it anywhere else.
I read about 2 temperature thermostat for OFF > LO > HI control, but I am not sure about speed input for LO > OFF control. Without this, electric fan conversion may not be worth the trouble. I was told by an automotive engineer that this is the primary energy saving and mileage.

Jbrew and White,
It is not "we figured it out". Automotive engineers are already using the setup in newer cars and pickups, including F150. Aftermarket merchants and e-fan conversion enthusiasts are merely catching up.

mbb

They been using them a looong time in front wheel drive cars. Being able to turn engine sideways and really cram things in under hood allowed front ends to get shorter, cars to be re-engineered, weight to be saved, simpler transaxle designs, higher mpg.

How to robustly retrofit these trucks is a different question. Overall, its proven best technology for most vehicles on road today.

Jbrew

It is not what?

Jbrew

Well, E-fans were around before this truck was. The Mark VIII launch was early 90's.

Iduno, most likley I agree, always leaned in that direction anyway. Controllers have come a long way. Perhaps that's one you mean by catching up lol. Regardless, a controllable amp less draw seems to of been the issue that caused the controversy. I was hoping you could shed a little light on what you've learned, but that's okay.

Good Luck, hopefully others will chime in that can help you out adding to mbb's post.

Wolvee

I won't say it adds power but I can tell a difference driving up a hill near my home. i've driven it from a stop twice a day since I bought my truck and the difference I felt in the truck was like night and day after switching to Electric fans.

Too many variables in a butt dyno and I could care less about 10hp anyway. +/- that you'll never really feel a difference but I can say I noticed in that specific instance. From a stop, up a hill to reach 45mph.

My controller turns the fans off at a speed I choose by the speed sensor. It turns on when the A/C is turned on AND I get to choose the percentage they turn on at temp and at what point they run 100% by final temp. ..and I have an override on and off.

Jbrew

I had Taurus fans for mine, came out of the same year vehicle, a 98. I trashed them cleaning up the garage one spring. Man I regret throwing stuff out at times, get tired of moving it around I guess.

If you have a the factory Alt in the 98 and it's a 130amp, it's really not. Stop by just about any 3rd party shop and load test it. They actually run up to 165amp. The factory original anyway. Still using mine...they don't build them like that anymore. I've never had a Alt last me this long. The owner of RJM and Ford Fuel Injection were I use to get all my Ford elec stuff informed me they these alt in 9th gens, carried over to the gen 10 but only made it in the 97/98. The 99's and up came with the same alt, rated 130amp, but from 99 that was indeed the MAX output. Check it out if you still have yours... it'll LT to 165amp.