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Here's the kit I used to install the electric fan on my 71 98. Even if you don't want to buy the kit the Jegs website provides instructions that are stupid proof. Follow the wiring schematic.
Here's the kit I used to install the electric fan on my 71 98. Even if you don't want to buy the kit the Jegs website provides instructions that are stupid proof. Follow the wiring schematic.
That Jegs kit requires a separate temp sensor, which can be a problem on some intakes. Do the Google search I suggested and you'll find an aftermarket box that reads your existing gauge sender and operates the fan, which is what the OP was asking for.
I've installed several over the years. I have one in one of my own cars that has been working perfectly for about 8 years now. These controllers work based on the outlet temp of the radiator, with a push-in probe that fits between tube fins close to the outlet of the radiator.
Why does anyone need a PWM controller for an electric fan? It's just an on/off control. I've had no problems with one of these capillary tube fan controllers. The capillary tube goes in the upper radiator hose and simply turns a switch off or on. The screw adjusts the actuation temp by controlling spring force on the switch. No muss, no fuss, no electronics. $35 on Amazon.
Let's point out the elephant in the room.
Why do you want to add electric fans?.
This has been beaten to death, revived and beaten to death again and again on this forum, but almost always fixing a stock system cures all overheating woes.
If your cars overheats on the highway fans will be no help to you.
But maybe you have a custom built car with particular needs?.
I'm not trying to be a smartass, just curious.
We all understand the loss of HP and torque using a plain or flex fan, clutch fan setup vs electric units. This is also compounded by any loss due to other accy's, alternator and A/C compressor, and water pump. My viewpoint is if your not racing the car why change if the factory stock system works for your car? The additional cost does not warrant the mod.
We all understand the loss of HP and torque using a plain or flex fan, clutch fan setup vs electric units. This is also compounded by any loss due to other accy's, alternator and A/C compressor, and water pump. My viewpoint is if your not racing the car why change if the factory stock system works for your car? The additional cost does not warrant the mod.
Personally? I'm going to be getting the air conditioning system back up and running. Currently the car has a single row 1-800-radiator in it with a Hayden hd clutch. I don't trust that tiny radiator to cool the 355 with all systems running in the summer heat. For 300.00 I get (at least from the eye test) a superior radiator and the electric fans free up the parasitic drag that the newly installed ac compressor will create.
Just out of curiosity, where do you think the electricity to drive the electric fan comes from? Hint: the alternator is also a horsepower sink.
The mechanical clutch fan still moves way more air than the electric, with less complexity and far fewer failure modes.
I'm looking for the best option for cooling. The radiator comes with the fans. If everything fits and works better I'm not opposed to the clutch fan, it has served me faithfully. I just assumed on a spirited journey from 2k-6k that the drag from the clutch fan would be stronger than the drag of the alternator, perhaps I'm wrong. With the AC compressor belt back on and clutch fan removed I believe I have the best option that I'll never have to hear the belts. Again. (short of a serpentine system, of course). I really am grateful for the input, thank you.
I'm looking for the best option for cooling. The radiator comes with the fans. If everything fits and works better I'm not opposed to the clutch fan, it has served me faithfully. I just assumed on a spirited journey from 2k-6k that the drag from the clutch fan would be stronger than the drag of the alternator, perhaps I'm wrong. With the AC compressor belt back on and clutch fan removed I believe I have the best option that I'll never have to hear the belts. Again. (short of a serpentine system, of course). I really am grateful for the input, thank you.
If your priority is cooling, the clutch fan moves more air. I'll also note that moving X amount of air requires a given amount of power, whether that power comes from electricity provided by a motor-driven alternator or directly from a motor-driven fan. I'll also note that the more conversions you have (mechanical power to electric to mechanical vs. just straight mechanical) the more losses you have.
I know we've covered this in the past, I recall discussing it with Oldsguy. Does a high load actually require more HP to turn the alternator than a small load? Or, does an alternator require a given amount of HP to turn regardless of load?
Whatever, the answer I think Eric's point is valid. Unless you're racing a car you aren't going to see any significant benefits to installing performance parts. For me it's more about buying toys than it is going fast. I know my DD Kia Sorento could probably beat my 71 98 in a 1/4 mile any day (as long as I don't burn out too much in the Kia).
Does a high load actually require more HP to turn the alternator than a small load?
If it didn't, you'd have perpetual motion. Is there any system that can produce more power output without increasing the power input by a comparable amount?
Note that new cars control alternator output via the ECU based on need to reduce the load the alternator imposes on the engine.
I believe all cars with electric cooling fans automatically run them if the A.C is on. A clutch fan will also pull air through the condensor, I don't see any real world gains there.
Can I let go of the baton now?, I want to play outside now it's stopped raining...
Why does anyone need a PWM controller for an electric fan? It's just an on/off control. I've had no problems with one of these capillary tube fan controllers. The capillary tube goes in the upper radiator hose and simply turns a switch off or on. The screw adjusts the actuation temp by controlling spring force on the switch. No muss, no fuss, no electronics. $35 on Amazon.
- PWM provides a more steady temperature, in contrast to the controllers that will cycle the coolant temps 15 or 20+ degrees.
- A PWM is not just an "on/off". It pulses the current, only providing as much as needed to maintain the coolant temp. If your cooling system is very good, your fan will never even reach full speed.
- On/off switches (like in the picture) cause voltage spikes, which can cause other problems. PWM controllers are much more gentle to the electrical system. I've seen alternators fail with the on/off switches, but never with a PWM.
SUMMARY: PWM controllers act similar to a throttle, providing just enough fan speed to control the temp. On/off switches are either full-speed or off, causing coolant temps to jump up and down, and causing voltage spikes in the electrical system.
From personal experiences, the thread in thermal switches fail a lot and the push in the fins of the rad controller also work when they feel like it. I actually removed the dual Dodge Stratus fans which move a lot of air and went back to the reliable factory 4 blade fixed fan.
SUMMARY: PWM controllers act similar to a throttle, providing just enough fan speed to control the temp. On/off switches are either full-speed or off, causing coolant temps to jump up and down, and causing voltage spikes in the electrical system.
Of course, this is where I point out that my mechanical clutch fan causes exactly ZERO voltage spikes...
Seriously, new cars take advantage of the tight temperature control to minimize emissions and eke out the last few drops of gas mileage. Musclecar vintage engines frankly don't care about a 15 degree variation in temp - heck, you've got a larger variation from one end of the cooling jacket to the other. If this complex system helps you sleep at night, have at it. It's one less thing to break on my car.
The cars rolling off the line today have electric fans or mechanical clutch fans, and the only thing that dictates that is the mounting of the engine, ie, all transverse "sideways" engines get electrical fans, all longitudinal "old school" engines get the clutch fan.
Even the 7GR engine, which we stick in damn near every Toyota (it's a 3.5L V6) gets the electric fan when it's a FWD car and a mechanical fan when it's RWD. Same exact engine, and pretty close to the same radiator. Camry/Highlander/Sienna vs Tacoma pickup, if anyone wanted to know.
Engineer hat:
Referencing Joe's comments about perpetual motion above, you will not get more power, or less drain, going electrical, given the same fan performance. You may have a better fan (bigger, more pitch) and it may cause a little more drag as it's doing more with a mechanical, as it's usually a bigger fan. This is why electrical fans are often two fans in one shroud, which, aerodynamically, is less preferable than one mech fan with a good shroud.
The only advantage I see to electrical fans is independent control. You can leave them on running on battery with the engine off, or, in cold weather applications, not turn them on until a certain temp is reached (beats a grille blanket.)
I have a dual electric "puller" fans from Flex-a-lite on my 64 F-85 build with an aluminum radiator. I have them set up to kick in when the A/C compressor is engaged or the temp hits 160 degrees, the temp probe is plumbed into the intake manifold. I have a 160 degree thermostat too. Though the car has not been in the street yet (hoping in a few weeks, I'll update my thread) its runs on the cool side but in this Texas heat and under a load we will see where the temp ends in traffic, long hauls with the A/C blasting. My plan is 185-195 degrees on the BB 67 Olds 400E. Just a few ideas to pass along.....
I've just watched the Engine Masters video.
One thing they didn't do when comparing fans was to have a forced airflow through the radiator. A 40mph and increasing gale howling through the radiator may well cancel any power robbing load from a clutch fan altogether as it would be spinning the fan rather than the fan drawing air. Less to gain from a fixed or flex fan perhaps. I'm not an engineer or have any special aerodynamics training, just an enquiring mind and a sense of scepticism developed from taking an interest in local politics.
I occasionally called in on a guy who used to do rolling road tune ups. He always had a big (mains powered) fan mainly to keep the engines properly cooled during the process. I didn't see anything like that on the engine masters video.
June 5th, 2017, 01:43 PM
