Author Topic: DIY Electric fan conversion (Read 112175 times)

naika · « **Reply #15 on:** December 19, 2009, 08:41:38 PM »

Thanks for the details.
Do you have any pics of your install?
I'm thinking of using an A/C harness but here in France, they are real hard to come by, so i'm going to have to wire it myself.

thanks

bmwman91 · « **Reply #16 on:** December 21, 2009, 01:51:54 PM »

Here's a fun thought...rig up a control system that measures engine RPM and speeds up the fan accordingly! It's like an electric version of the clutch fan.

Of course, theoretically that might be less efficient since you have to include power losses in the alternator, wiring, fan power controls, etc. Maybe you could design in a big delay so that it does not really spin up while the motor is revving up, but rather once it has settled. Hell, have it measure vehicle speed too & turn off above 30mph.

Or just keep doing what everyone has been doing since that is simple & it works.

Voluted · « **Reply #17 on:** January 26, 2010, 11:50:52 PM »

I know i'm bumping this old thread again, but couldn't you just use the existing AUX fan wiring to wire the new fan up? The AUX fan has 3 wires going into it. I am pretty sure this is their function:

Black - Fan low speed
Red - Fan high speed
Brown - Ground

The AUX fan circuit is tapped into the coolant temperature switch mounted on the left of the rad, which activates the low speed setting at 91C, and the high speed setting at 99C. My understanding is that the ceramic resistor located on the aux fan is what controls the speed of the fan.

At least this is my understanding of it. If anyone has conflicting info please chime in.

Also, i deleted my A/C a couple days ago and will be trying my AUX fan for primary cooling as a pusher. I will try the current temp switch and switch to the 318ti (81C/88C) switch if i need the fan to turn on sooner. The pain is trying to figure out how to mount the fan in a clean and solid way. I made a bracket out of steel for the top already, i suppose I just have to make a few more. Anyway, i'll let you guys know how it goes once i test it and i'll shoot some pics.

DesktopDave · « **Reply #18 on:** January 27, 2010, 07:01:28 AM »

I was thinking of doing that myself. I'm thinking that the wires or thermo switch wouldn't handle the load of a really big rad fan permanently. I'd also have that fan kicking on every time I switched on my A/C. You've deleted it, so it's not an issue. Might actually be an advantage to you...use the A/C button as a manual override!

You might be able to get away with just the aux fan if you dilute your coolant mix & add a few bottles of water wetter/purple ice/surfactant of your choice. Worked like a charm on my E34 525i. There are a lot of E36 M52 guys running that system with the low temp e36 thermo switch.

doitover · « **Reply #19 on:** January 27, 2010, 09:55:46 AM »

I've been running without either fan for over a year. Except for high 90's days sitting a traffic lights it has never gotten over it's normal position. I do plan on finally putting in an inexpensive electric fan before this summer but they don't seem to need much.

Voluted · « **Reply #20 on:** January 27, 2010, 10:34:19 AM »

That's good news for me Dave as i'm putting my M50 in the car in a couple months when it's warmer outside. I wanted to do the aux fan thing now since I sit in traffic on my way home from work and i don't want to be testing it on my new motor. I have full confidence in the stock AUX fan after giving it 12a of power; it blows a lot of air.

Last year in the spring i ran my car with no fan and it was great as long as i didn't hit traffic. After about 5-10 minutes of stop and go the temp would creep up to the 3/4 mark at a quick rate and it would start to overheat. As soon as the car was moving past about 30km/h the temp would quickly move back to 1/2. The car is actually a lot quieter with the fan off i have noticed, i'm really looking forward to it!

DesktopDave · « **Reply #21 on:** January 27, 2010, 11:22:01 AM »

I suspect we'll gain a little power from cutting out the engine fan too. Not much, but every little bit helps. I prefer it because throttle response improves. More importantly, you'll have some space in front of the motor.

Vladi · « **Reply #22 on:** January 28, 2010, 03:37:56 AM »

Swaped the aux fan for an E32 750i fan(using the pre-existing E30 OEM installation and two speeds), viscous clutch out in the garbage, used BMW OEM 80/88 temp sensor from an E36 Compact 316i '99.
Works absolutely perfect even during summer and 100F temps the needle would never go beyond the half mark and even then I've heard the second speed kick in rarely.

JP 91iS · « **Reply #23 on:** January 30, 2010, 11:50:26 PM »

Quote from: Voluted;85763

I know i'm bumping this old thread again, but couldn't you just use the existing AUX fan wiring to wire the new fan up? The AUX fan has 3 wires going into it. I am pretty sure this is their function:

Black - Fan low speed
Red - Fan high speed
Brown - Ground

The AUX fan circuit is tapped into the coolant temperature switch mounted on the left of the rad, which activates the low speed setting at 91C, and the high speed setting at 99C. My understanding is that the ceramic resistor located on the aux fan is what controls the speed of the fan.

At least this is my understanding of it. If anyone has conflicting info please chime in.

Also, i deleted my A/C a couple days ago and will be trying my AUX fan for primary cooling as a pusher. I will try the current temp switch and switch to the 318ti (81C/88C) switch if i need the fan to turn on sooner. The pain is trying to figure out how to mount the fan in a clean and solid way. I made a bracket out of steel for the top already, i suppose I just have to make a few more. Anyway, i'll let you guys know how it goes once i test it and i'll shoot some pics.

Here's some info I'd gathered for some other people:

Threads:
ACSchnitzer318is volvo fan thread - Wiring Info

Electric Fan Install General Info

gearheadE30 volvo fan thread

Fan delete part numbers

Basically:
1)Fan:

Quote from: tjts1;60176

All 92-98 volvo 940, 960, 850 will have this same fan.

People have also successfully used the stock aux fan alone as a pusher or puller. It just depends on your climate and driving styles. This Volvo fan just pulls more air so I chose to go that route.

2)Shroud Cutting:

Quote from: JP 91iS;68757

Shroud after I modified it. It fit almost perfect when I turned it sideways so I cut it to the proper height and used some of the extra leftovers to fill the holes along the bottom. I also had to trim a bit off one side.

I used the volvo shroud that came with the fan because it sits flush with the radiator to allow more room in the engine bay. You could a)cut it to the same width as your radiator or b) turn the shroud sideways and cut it to the same height as your radiator. Just hold it up and try different fitments until you find one you think is best. Mark it with a sharpie and cut it. I used a hacksaw but a dremel cutting wheel might work better. You'll have to just cut here and there until you get the shroud to fit, just use the leftover scraps to cover up any big holes on the shroud portion you are going to use.

Also take note of how the fan mounts to the shroud when considering shroud mounting so you can point the fan wires where you want to run them.

3)Shroud Mounting:

There are some holes along the top and bottom lip of the radiator, one at each corner. I used a small nut and bolt at each hole. I made a couple extra holes near the middle of the bottom edge and used some zip ties to help pull the shroud in close to the radiator.

4) Wiring the Fan to the Auxiliary Fan Circuit:

Follow the wires that come from the Auxiliary Fan. That is the fan mounted on the front of the radiator. Its much easier to work in there if you pull off your grilles, headlights, front bumper and valence. But you may not need to take all that stuff off.

Quote from: AcSchnitzer318is;60207

Brown on car goes to black on fan, black on car goes to green on fan, and red on car goes to red on the fan. Hope that helps.

The wiring to the aux fan routes along the bundle of wires below the drivers side headlight. There are 4 wires going into the fan. There is one black one that loops through a resistor on the fan- it just looks like small, long black box. You don't keep this box when you install the volvo fan. Use the black wire that runs into the box to wire the volvo fan- just cut and tape off the extra black wire.

Quote from: JP 91iS;68757

Wiring route. I ran it under the radiator then up the side through the holes in the frame and soldered it to the plug that used to run to the aux fan. I had to extend the harness about a foot to reach the wires on the fan.

5) Extra Parts

This stuff is not necessary, only helpful in hot climates.
I did some extra stuff to ensure this fan would be enough since I deleted both my clutch fan and my auxiliary fan. I replaced the thermostat with an 88� one, and I replaced my temperature switch with an 80�/88� one, and added a bottle of Redline Water Wetter to my coolant.

Quote from: JP 91iS;68875

88� thermostat (PN:11-53-7-511-580)

Thermostat O-Ring: 11-53-1-721-218
Thermostat Housing Gasket: 11-53-1-721-172
80�/88� Dual Temp Switch: 61-31-8-361-787
Fan Switch Washer: 32-41-1-093-596
Bought my Water Wetter from BavAuto

Good luck with the install

dwtaylorpdx · « **Reply #24 on:** January 31, 2010, 02:28:07 AM »

If you ever need a rocking electric fan, check out a ford Tauras, LTD etc. Needs a heavy relay but the sucker move radical air....

Dave

jeff_b · « **Reply #25 on:** February 16, 2010, 08:08:06 AM »

Voluted--How did it work out? Still cold up there in the Great White North, eh?

jeff_b · « **Reply #26 on:** March 23, 2010, 10:03:19 AM »

bump for reply

Voluted · « **Reply #27 on:** April 21, 2010, 01:45:46 PM »

Well, I have been driving with no fan since that post and we are finally seeing some warmer days here. I am happy to report that the stock aux fan does more than enough to keep the engine cool!

Few things to note:

- The longest i sat in stop and go traffic was ~40 minutes and it was ~25 celcius outside
- Since i still have the stock coolant temp switch (fan switch) the engine heats up to the 3/4 mark on the guage before the high speed kicks on.
- If i press the A/C button the low speed setting of the fan is engaged and the engine NEVER crawls past the 1/2 way mark on the guage
- There was no need to have my fan on unless i was sitting in traffic for over 15 minutes. The high speed setting (when i let the engine reach 3/4 on the guage) would bring the temp back to 1/2 within a minute.

Compared to when i took the fan off last year I am seeing a significant increase in cooling now that there is no A/C condenser in front of the rad.

For reference, i used the OEM euro brackets to mount the aux fan which i purchased from BMA auto parts for about 10-15 bucks for the bigger two and under 5 for the small cup.

There was no re-wiring and I was able to use the old hardware on the fan to install it to the brackets. I needed to by two speed nuts to skrew the mounts on the top of the rad support. If I remember, I will take a few pictures of the fan on my car tonight. I also did not use any water wetter or any similar product or run a cooler thermostat.

Seriously, this has to be the easiest mechanical thing i have done to the car to date and one of the more satisfying ones. To get the fan in/out I undid the upper rad support then lifted the rad and pulled it toward the engine. The rad has rubber bumpers sitting in cups on the bottom to hold it in place so it is easy to reposition afterwards. The hardest part was jamming the rubber peices into the mounting brackets.

Here is the picture: The two upper brackets needed to be swapped on my car for some reason since they didn't mount the fan properly the way they show them to be mounted.

http://www.realoem.com/bmw/showparts.do?model=1111&mospid=47263&btnr=17_0073&hg=17&fg=10

jeff_b · « **Reply #28 on:** April 28, 2010, 09:30:51 AM »

Voluted--Excellent reply! This is exactly how I was going to do mines, save for the euro mounts, which I will order for my installation. It really is an EASY modification, with an arguably tangible benefit, not to mention improving the engine bay aesthetics. All my shit is out of the car right now, waiting for me to finish up with the engine and bay cleaning/refreshing.

Nice work!

carguy101 · « **Reply #29 on:** May 27, 2010, 01:57:43 PM »

I just installed the Volvo two speed fan. I dont know if this has been covered but I ran the power to the accessory fuse block. There are two wires a green and a red one. I ran the low speed to the ignition on which was red IIRC and the green to a switch to operate the the high speed fan that is able to be turned on whether the car is on or off without the car running, say while sitting in the paddock at an autox. I used one of the window breaker switches and put it in one of the factory slots above the radio so it looks original.