M50 Electric Fan Conversion

[Singing6]

Hey all,

I know there have been some spectacular threads on electric fan conversions in the past, but I though that I would throw my hat in the ring so to speak.

I chose the Spal VA33-Ap71/LL-65A fan and will be mounting it to a custom shroud. The shroud is made of 1/8" aluminum sheet and will mount to the OEM slots on the radiator.

I'm hoping that this system will work well enough that I do not need to have the aux fan in front of the condenser. If this is not the case, however, the aux fan will only be controlled by the HVAC module (it turns on if the A/C is on).

The stock 90/99 C temp switch has been swapped out for the 80/88 C switch for the E36 318i.
Screen Shot 2018-06-01 at 6.35.35 AM.png
I started with a simple CAD drawing and then used it to make a cardboard template for test-fitting:

IMG_5238.jpgIMG_5239.jpgIMG_5240.jpg

The test fit showed small things that needed adjustment. Glad i did it on cardboard first!

Engineer in training,
Singing6

[zkd]

I found a Better solution and it worked fine with out the conversion:

what you do is very easy. if your car is fitted with AC, then all you have to do swap the the cables of the Fan Temp Switch on the radiator. this allows the AC fan to go full speed when water temp goes above 80c. this actually keeps my car cool specially in traffic. and it will not interfere with the normal operation when the AC is on.

s-l300.jpgTemp sensor.jpg

[Hofmeister]

I mounted mine using
https://shop.advanceautoparts.com/p/...E&gclsrc=aw.ds
And found which of the two wires going to the aux fan worked for the trigger and ran it off of that. Also swapped the wiring like the above poster said.

[Singing6]

One of the objectives of this mod is to remove the mechanical fan and its associated systems. My viscous coupling is dying and I am using this as an excuse to replace it with an electric fan. There is much more control with an electric system. Another reason is ease of removal, this will be much easier to work with than that mechanical fan.

The reason that I am making a proper shroud and not just ziptie it to the radiator is for airflow reasons, same applies to just using a pusher fan; this is not as simple as a Chevy, it may take some work to IMPROVE the system. This system has to keep the engine cool with the A/C on full while the car is stationary in +100F Virginia. If your setups can do that (without a mechanical fan) then I will be interested.

- - - Updated - - -

That being said, I do like the idea of using the aux fan wiring as a trigger.

[Hofmeister]

One of the objectives of this mod is to remove the mechanical fan and its associated systems. My viscous coupling is dying and I am using this as an excuse to replace it with an electric fan. There is much more control with an electric system. Another reason is ease of removal, this will be much easier to work with than that mechanical fan.

The reason that I am making a proper shroud and not just ziptie it to the radiator is for airflow reasons, same applies to just using a pusher fan; this is not as simple as a Chevy, it may take some work to IMPROVE the system. This system has to keep the engine cool with the A/C on full while the car is stationary in +100F Virginia. If your setups can do that (without a mechanical fan) then I will be interested.

- - - Updated - - -

That being said, I do like the idea of using the aux fan wiring as a trigger.

each system has pros and cons, mine is simpler and cool better in motion as air can flow clean through without obstruction. yous i tougher to sea and requires much more powerful fan. my way has kept my engne and ac col with both fans at low speed in south florida summer trafic.

[fo3]

I'll take photos of mine when I can.
I mentioned before mine has an aftermarket capillary bulb and mechanical thermostat that I like to get rid off. I also don't like the way it's connected straight off the battery (the previous owner installed this fan), but while doing my cooling system I fitted the 80c radiator aux fan switch in preparation for rewiring.

Anyway, now I've changed the engine thermostat, the electric rad fan doesn't run while driving (temp stays on the half mark). Fan only runs after I have switched the engine off (as you know the temp goes up slightly when the water pump stops and no airflow), so I have the mechanical thermostat for the electric fan set up perfectly right now I think - only runs when just over the 1/2 way mark on the dash gauge.

But show me a way to get rid of that mech stat, capillary bulb and the fan running after I parked the car, but not hacking badly or disable any function the factory aux fan and I'll rewire mine the same.
E: by that I mean I don't want the aux fan to come on high speed, or to do something that will stop the aux low speed coming on with the a/c, and also not have the aux fan low speed to come on at the same time as the elect radiator fan. I tried to work something out control wiring wise because the fan relay box has room for an extra relay but I gave up after realising that while my aux fan works on low for a/c, I could never get it to come on for engine - even though I disabled other the fan and have replaced the radiator aux fan switch for a 80C part.

[Singing6]

Updates!

The prototype of the shroud is cut, will be test fitting tonight and seeing how it performs in the heat as well.

IMG_5271.jpgIMG_5272.jpgIMG_5273.jpgIMG_5268.jpg

I'm almost positive that the baffles will hit the drive belts if fully open, but will test first before coming up with a solution to restrain them.

[Singing6]

Learned a bit after two weeks of testing:
-starting current for this fan is higher than spec (25.4 Amps) because it keeps popping the 30A fuse after a few startups
-the thick flaps don't work as well as expected
-single stage control is perfectly fine

The way that I have it wired up is triggering off of the 80C switch, disconnected form the AUX fan. I confirmed that the Aux fan still comes on anytime the compressor is in operation. I also tested that the low speed switch stays closed even when the high speed switch is closed (I.E. the fan wont turn off when the temp is above 88C). I wired the power for the relay from an always hot source.

Recently got to see an E46 AUX fan up close and noticed that it used hard flaps instead of flexible ones. I am going to try to do that as oppose to the flaps.

Singing6

[e30luv318i]

If you produced another one of the fan shrouds I’d buy one off you

[Hofmeister]

Learned a bit after two weeks of testing:
-starting current for this fan is higher than spec (25.4 Amps) because it keeps popping the 30A fuse after a few startups
-the thick flaps don't work as well as expected
-single stage control is perfectly fine

The way that I have it wired up is triggering off of the 80C switch, disconnected form the AUX fan. I confirmed that the Aux fan still comes on anytime the compressor is in operation. I also tested that the low speed switch stays closed even when the high speed switch is closed (I.E. the fan wont turn off when the temp is above 88C). I wired the power for the relay from an always hot source.

Recently got to see an E46 AUX fan up close and noticed that it used hard flaps instead of flexible ones. I am going to try to do that as oppose to the flaps.

Singing6

IIRC the volvo fan uses soft rubber flaps, theyre 1/3 the size of yours though and very flexible.

[Singing6]

I realized pretty quickly that the thick flaps do not work as well as may small ones


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[Singing6]

If you produced another one of the fan shrouds I’d buy one off you

PM me


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