Hello All

I have been thinking about doing an electric fan conversion for a while. My big concern is if the car has the voltage neccessary to run one, and how to sense the temperature to turn it on.

My car is an 88 245. I allready have a pusher fan that turns on with the AC compressor. After the car would not start at a gas station, I found that with the daytime running lights, AC and inside blower on, the cars voltage dropes below 12 volts. I had been running this way for some time and was apparently running down the battery.

Has anyone else had this problem? and if so how did you overcome it?

Allso My new 3 row radiator has a temperatature switch or sensor in the upper right hand corner. Can Use this to start the new fan?

Thanks in advance
Joe

I am still not sure what gain, if any, one can expect using engine power to generate electrical power for a fan vs. direct use of the viscous coupled engine fan. Is anyone able to explain why this is not a perpetual motion type (specious, false) thermodynamic argument?

rhaire

The fan cluch went bad on my old volvo. When it did I noticed a seat of the pants feeling of more power. Or I should say the engine would gain RPM faster and felt like more power. The drawback was the overheating thing.

I have read of the e-fan conversion and was not really considering it untill my new 3 row radiator showed up with some sort of temperature sensor built in.

Joe

Well, feeling like more power is just not evidence for more power. The placebo effect, in a lot of casest, it is all just too subject to our imaginations. Sorry, gotta have numbers, dyno data, times, something real to make that call. Ram air mods, foam air filters, additives, snake oil. I am not saying you did not have a little more power, I am just saying we can't tell from seat of the pants feelings.

Bob,
A good viscous fan clutch always has some drag on the engine, even when cold. The electric fan only comes on when it's needed, also the battery acts as a buffer so the demands on the alternator all at once is not as bad as you might think.

I've got a 940 fan and I'm in the middle of changing over, hope to fit and wire it this weekend. If nothing else it makes for super easy belt changes.

I'm wiring up a tattletale light to see just when the fan is working, from what I've heard it's only when standing still but it will be nice to know for sure. Plue if no benefit is found it's easy to switch back.


--
Dave Shannon
Spring Valley, California
'67 1800s
'73 1800ES
'88-240
my pages

OK, so it is a peak performance hp thing? WOT, no drag now, recharge later. Hmmm, might be easier than the liquid nitrogen tank I have envisioned on the relatively flat hood.

Yes, it is a peak torque thing. Like reducing the weight of the flywheel. Another great improvement is turning the alternator and aircon pump off whenever you are accelerating. Not as hard as it sounds, but needs some electronics.

The electric fan will only come on when in the city at a traffic light in summer. Otherwise it is not needed, because Volvo radiators are overengineered. I'm about to do the same conversion.

I think that's about it. It's supposed to be quieter, even compared to when the fan clutch is not engaged, also rumored to prolong water pump life.

Real bottom line is people think it's cool.
--
Dave Shannon
Spring Valley, California
'67 1800s
'73 1800ES
'88-240
my pages

One writer claimed to get an extra 2 mpg from the conversion.
I'd like to do the conversion myself, but haven't gotten to it yet.
I've got other 240 maintenance projects ongoing.

Yep, that's why I've had the parts laying around for over 3 months, too many projects too little time. I'm looking forward to an estra MPG or 2 also. I get a very consistant 20-21 measured over the last few years so if it jumps to 21-22 or better I'll know what is causing it.

--
Dave Shannon
Spring Valley, California
'67 1800s
'73 1800ES
'88-240
my pages

Some contributors here have done the electric fan conversion with success. I don't believe there's an electric fan out there with the air-moving capability of a properly functioning engine-driven fan - except perhaps at very slow engine speeds in stop-go traffic. If that describes your driving situation perhaps an e-fan is right for you.

If you are seeing battery discharge under normal driving conditions with your present electrical loads, it sounds like your alternator is not up to par. It should be an 80-amp unit (peak output), well capable of handling the demands. Most auto parts places that sell rebuilt alt's will do a free on-car test of yours. If you have a voltmeter you can do your own check. Our 83 (70-amp unit) will deliver 13.5 volts at the battery terminals at a 1000RPM engine speed with high beams (4 lights), heater fan, and rear demister all going. You should see similar or better results.
--
Bob (son's 81-244GL B21F, dtr's 83-244DL B23F, 'my' 94-944 B230FD; plus grocery-getter Dodge minivan, hobbycar 77 MGB, and a few old motorcycles)

Volvodad

Thanks for the reply.

" it sounds like your alternator is not up to par."

I think you are right. At 1000RPM (and more) with AC and AC blower as well as headlamps. 88 model only only has the 2 headlights. The voltage will drop to around 11 to 11.5 volts. keeping in mind the AC also turns on the pusher fan on the front of the car.

Bottom line is I can have lights or AC, but not both.

I fabed up a bracket and threw a chevrolet alt in and it now only drops to 12.25 volts. Not really great but at least not discharging. I feel that any additional load would drop it down below 12 again.

I can get a 100amp gm alternator new for $70 as opposed to a rebuilt volvo one for $140. I dont want to trust a junkyard part.

It would not be very smart for me to attempt an e-fan conversion until I get this sorted.

Thanks

Joe

The most I've ever seen a junkyard Volvo alternator need is a new brush pack. Last brush pack I got was $39 and that was at the dealer. Since then I pull the pack and look at the brushes before buying it. If the brushes are short I look for another one. If you look around you can get a perfectly good 100A unit for <$20 that will bolt right in.
--
Dave Shannon
Spring Valley, California
'67 1800s
'73 1800ES
'88-240
my pages

I've had some experience with swapping GM (Delco-Remy) alternators into other cars. The old "SI" series were a capable but unsophisticated unit. Reliable and moderately high output, but big and heavy, and produced a lot of electrical noise. With a good stereo, you needed noise suppression chokes on the input leads or there was a lot of alternator 'whine'.

I really think you should try to get a good deal on a Bosch. I've found wrecked 700-series cars in the PnP with freshly rebuilt 80-amp and 100-amp Bosch's...$15. If you do go for a Delco, the only one I'd endorse is one of their "CS" -series. Small, light, nicely made and electrically quiet. You'll probably have to swap on a V-belt pulley to work on your Volvo. And if you can actually get one for $70 - wow.
--
Bob (son's 81-244GL B21F, dtr's 83-244DL B23F, 'my' 94-944 B230FD; plus grocery-getter Dodge minivan, hobbycar 77 MGB, and a few old motorcycles)