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The system components and design are pretty much standard items no matter who makes them. The only thing one really needs to know is how much air the engine wants the fans to move and for our 928's that number is about 3000 CFM and that will require about 30 amps or so to deliver it so the first point to be addressed is whether the alternator has such ampage in it as a model with a mechanical fan will not have such built into the rating [or so I would think] thus one would need a later type alternator and any requisite supporting infrastructure. The S4/GTS alternators are not noted for having excess capacity thus the bigger ones supplied by the likes of Greg or Carl can supply would be a useful adjunct to such a project
Folks like SPAL have rather neat integration packages including programmable controllers and wiring/relay harnesses for quite reasonable bucks. The later 928's have wiring direct from the battery positive post to the fan elements in order to reduce voltage drop- something similar would likely be needed. Sensors for temperature control can be mounted in readily available adapters that splice into the cooling hoses if the stock radiator has no boss for mounting of such. If I were going to do such a project for sure I would use the SPAL dual 12 inch fan setup that can had for about US$300 and there are even better aftermarket options at whatever coinage is required.
Such a project is going to cost the best part of US$1k.for decent quality materials.
OP - yes that will work. Not even necessary to use the Volvo relay pack, you could just use a single standard high-current relay (look for Ford Contour fan relay, it's a standard size relay but 70A capacity).
the volvo fan controller (and the mating Fan off of those 850/S70/V70 models) is excellent.
the Volvo fan is essentially a downsized version of the Taurus fan - about 15" blade vs the ~16 or so of the Taurus, same motor too.
I have 2 of these fans and their controllers in my garage.
SPAL stuff can't touch it, and nowhere near $1000. You can get the Volvo fan + relay box for about $30 at most pick-and-pull yards.
HOWEVER there is an even better fan option from Volvo that is a near direct-match fit for the 928 radiator (shroud has very close dimensions to the 928 rad core)...off the 2000's era Volvo S60. Slightly "thinner" than the Taurus too.
I used one of them on my 944 for several years...it would make a breeze at the BACK of the car, it moved so much air.
See my thread here...note that 928S4 fans are about 3" taller than the 944 fans pictured.
If you open up the "fan controller ECU box" you can cut the actual power wires and splice regular wire connectors to the motor. the little box is a PWM controller.
The switch in the radiator is a standard VW part. Install a 3-way version in the temperature range(s) you need, and use that to switch the fans off / on as needed.
We've done this to many early cars, including two of mine.
Those VW Temp switches come in a wide range of temperature options.
I've been running one of those taurus fans on my Durango for years now.
A couple things I can tell you are that you probably want about a 50 amp fuse to run it. On high, it draws a good bit of power. My original alternator on my Durango was 117amp, and at idle it could maintain, but not charge the system with the fan on high. I now have a higher current (allegedly 200amp, but I don't believe it's actually that high) alternator on it and it's fine.
As far as relays, I originally ran the 70amp relay that came with my dakota digital controller for it. The relay itself seemed ok, but the contacts kept getting hot where the relay connected to the wiring and it started melting the connector. I've since switched over to the volvo hi/lo relay, and not only does it simplify the wiring and make less clutter, it has had no problems keeping up with the power draw.
You need to make sure you use good thick wiring for it too. I think I'm using 10 gauge right now, and honestly would probably use 8 or 6 if I were doing it again. The wiring does get a little warm. Finding a fuse holder with good enough contacts to make a decent connection and not get hot was also a pain.
The only other problem I have is that the taurus shroud doesn't cover the whole radiator, so the bottom 4 or 5 inches aren't covered. When moving down the road this isn't an issue of course, but when sitting still it can be. That said, I've only ran into that once. I run a 180° thermostat in the Durango, and normally the temp is pretty close to the stat temp (controller targets 185). One day while sitting in traffic on the interstate for about an hour when it was over 100° out the coolant temp started creeping up and got to about 210° before I got out of the traffic. If I'd have turned off the a/c it probably would have went right back down.
I initially bought a depo new fan for $80. It failed in a year. I've been running a used one from the junkyard for years now without issue.
Here's a quick comparison I did of the flow freestanding and through the radiator.
One cheaper fan you can use is one out of a Lincoln MKVIII. Those fans will fit inside of the stock fan shroud itself with some aluminum spacers.
There are 2 variants. An early (93-95 IIRC) version with a 2 stage relay for low and high fan speeds and a later version with PWM control.They move well over 3000cfm and can be had for cheap.
What I recommend doing to power it is to use a PWM controller to start it slow and have it ramp up from there depending on temp.
These fans can take upwards of 90 amps to go from completely stopped to full blast 100% power. Continuous draw is around 30 amps.
I'm running a dual Ford fan setup with a PWM controller in my 83S. I am quite satisfied with the fit (covers all but about a 1/2" strip at the bottom of the rad) and how well it cools, but the alternator I have in the car now is not really enough. I have done the 'Delco' alternator install (it's actually a Hitachi alternator) and that did improve things compared to the original alternator, but when the fans are on high and the engine is at idle the voltage is really too low. I'm sure I'd be in trouble if it was night (lights on), raining (wipers on, blower on, rear defog on) and I was stuck in stop and go traffic. I do plan to upgrade to the later style alternator, but this is a major step. I am running a 5L hybrid, so I have the right M10 alternator bolt, but there is a "console" (928 101 123 02) to be replaced and that means you need to go to the later style P.S. pump (and pulley at the crank) as well as the new style alternator (and pulley at the crank). In addition you need the pulleys and belts for both the P.S. pump and alternator.
I am using a fan like this:
I picked it up for about $50 at a wreckers. It cleaned up nicely and has been working fine for about 20,000 miles so far.
I have some nice edging between the plastic of the fan and the fins on the radiator:
About $10.
The fan is attached to the radiator with some aluminum tabs I fabricated:
I cut away the lower part of the original fan shroud, and left the top part to hold the air tubes.
The fan controller is mounted where the air pump filter can would be if I had an air pump:
I am using the FK-50P controller from Delta Current Control. I paid less than $150. This model seems to have been superseded. The closest current models seem to be FK-45 or FK-75.
This setup is very responsive and does a good job of keeping the temperature between 82 and 85 degrees C. The temperature sensor fits in between the fins on the rad so no coolant plumbing adapters are needed. I have the temperature sensor about halfway down the rad on the inlet side. Below 82 degrees the fans don't run, and when sitting at a standstill in 30+ degree C weather the controller keeps the temperature no higher than 85, but the fans are running at a pretty high rate to do that. I do have the LED inside the cabin that changes from green (fans not running) through orange (fans at less than 100%) to red (fans at or near 100%) so I can see what is going on while driving.
I have no air pump and did try the short belt trick on the viscous fan, but after a while the mount for the old fan cracked up at the top and I already wanted another way. However, I would agree with the other posters that getting the original fan concept to work by replacing parts is most likely the simplest way.
The volvo controller sound good.. and OEM cooling solutions like that are usually better quality than aftermarket alternatives.. maybe pairing it with the dual-fan setup (the attraction being mainly that the shroud is a good fit too).
check out DC Controls. they make a wonderful progressive fan controller. i used it along with Hans shark blade fan set up. never got remotely hot. even with AC and stock thermostat
I have been using the Hayden digital fan controller with the wrecking yard ford contour dual fans for the last few years. I bought and installed the optional brass sending unit that screws into the port for the electric front side fan which I deleted.
Fans soft start to keep current spikes down and spins up full for AC operation. Works great even in the hottest of Texas summers.
The stock thermostat is 83C, low temp is 75C. The stock temp sensor thread is M22x1.5, and there are MANY switches in this thread available, both single and dual temps. I run a SPAL dual 11" set up with 83C sensor in the top hose, and it copes with southern Oz temps fine. The shroud covers better than 95% of the core. Watch out for people claiming 3000cfm airflow from their fans - SPAL do this on one of theirs, but note that its a racing unit, with a lower projected motor life. These are barely audible from inside with the bonnet shut.
jp 83 Euro S AT 57k
07-05-2018, 09:23 AM
Electric Fan Solution For Early Cars?
