Replaced clutch fan with electric fan

[X5chemist]

Nice work. How do you plan to seal the fan edge to shroud? Closing the gap will increase efficiency. I've seen peeps use can foam to flat aluminum pieces.

[workingonit]

I'm sure that'd improve efficiency, but it's probably not needed. I bought a fan rated at 3000 cfm (Flex-A-Lite 238, puller) which should be overkill for a 225 hp straight-6. I used only 4000 cfm for my 427's, even on the street, in Texas summertime.

The gap in shroud coverage isn't any worse than some factory fans have, in my experience, and better than using no fan shroud at all.

[bcredliner]

Wow, I didn't have to any fabrication. Took less than 3 hours from unpacking to all done. I don't see any need for an on/off/auto switch. If the fan is rated high enough, it just runs two to three shorts bursts in the hottest part of a Texas summer. The fan I have is rated for 600hp. The stock fan on the X5M runs much longer. Battery drain is not a problem on either one.

https://xoutpost.com/bmw-sav-forums/...ctric-fan.html

[workingonit]

As I stated, I tried to simplify my install, looking for a switched power source underhood (not finding a good one), and attempting to use the simplest attachment method (couldn't use the push-thru rods for lack of clearance).

When I decided to supply my own power thru the firewall, then I opted to add a manual override switch, as well, taking advantage of the "sleep" mode to power it. I used a cheaper thermostatic switch, but that can be changed later, if insufficient.

I'm waiting for the cigarette-lighter-plug power wire to complete the install. The aluminum frame/brace was a trick I've used before with pre-existing shrouds (for quick removal from race cars), so it wasn't a big deal. Actual time spent "fabricating" may be 4-5 hours, mainly from working in the heat, finding the right tools (spread out in about seven project locations), and being 70. I'm in no rush. And, I haven't done a fan install in 10 years.

I saw that you chose a Flex-A-Lite 118 (2500 cfm) for your 4.6L engine; I went as large as I thought I should for my 3.0L engine, a Flex-A-Lite 238 (3000 cfm). I couldn't find a fan with greater cfm, without a much higher current draw, so it should do. I usually overdo things, since I was always building up my race cars to a higher hp level...old habits never go away. Here's a chart that's pretty accurate about cfm requirements.

[bcredliner]

Even with a tune, meth and nitrous the fan has been more than sufficient. If I recall correctly I choose that particular fan because it was very slim so it left space to work on from of engine. I was concerned it was enough at the time but that has not been a problem.

Sounds like we have some of the same background. I raced Corvettes for a few years, club racing. All were big blocks and one was an L88. Overkill was standard operating procedure so I understand your reasoning.

[workingonit]

Originally Posted by X5chemist

Nice work. How do you plan to seal the fan edge to shroud? Closing the gap will increase efficiency. I've seen peeps use can foam to flat aluminum pieces.

Originally Posted by workingonit

I'm sure that'd improve efficiency, but it's probably not needed. I bought a fan rated at 3000 cfm (Flex-A-Lite 238, puller) which should be overkill for a 225 hp straight-6. I used only 4000 cfm for my 427's, even on the street, in Texas summertime.

The gap in shroud coverage isn't any worse than some factory fans have, in my experience, and better than using no fan shroud at all.

Here are two old-school fan shrouds, one with tight blade fit and open corners, and another with inset blade coverage but no uncovered radiator surface. The first one relied on a mechanical fan, and max (bypass) airflow at highway speed was needed over the open areas for cooling. The second fan, also mechanical, had covered blades for safety, but total enclosure of the radiator surface might compromise airflow at highway speeds (depending on blade angle/speed and how tightly the surrounding fit was).

Second photo is a BMW aux fan, which uses a shroud with extra flaps that open to allow higher flow past it, at high speed, to cool the radiator/condenser better. With this fan/shroud already allowing some airflow in around the edges into the radiator, the new main fan really doesn't need to fill the radiator-side shroud so tightly, since airflow is coming thru at high speed anyway.

I've run many electric fans on many vehicles, and installed them on many more...about 1/4 without any shroud at all (for oil & trans cooler fans, farm tractors, supplementary A/C condenser fans, and some drag race cars); if there was a fan shroud already there, I modified/adapted it to fit the new electric fan, or just mounted the fan alone (usually added a pusher-helper on the other side). I never had one fail, or the vehicle overheat (except when the relay failed...I plan to carry a spare).

Nowhere in the fan literature that came with my new fan, did I find any mention of requiring a fan shroud; the fan manufacturers shape these aftermarket fan housings to promote airflow with no other help, but they usually also offer aftermarket shrouds as well. I've seen cars/trucks even recently come from the factory without real fan shrouds, just a framework for fan mounting. So, I think that by using the existing shroud on my X5, it will allow sufficient airflow at all speeds, so that tightening the gap around the slightly-inset 3000 cfm fan won't be necessary.

[bcredliner]

Existing shroud works fine. Not an issue.

[workingonit]

I received the final part yesterday evening, and started to wire it up inside the cabin about 1 pm. Finished at 5 pm (after buttoning up everything about 3, then finding that the hidden manual override switch didn't work. It did before I buttoned-up, but not later.

So, I took it apart, verified that everything except the manual switch still worked, and searched in my leftover electrical parts (from racing), and found a 50A used switch. It worked; but I had to change my hidden location to another, so it took me awhile to put it just above where the clutch pedal would go (the plastic panel there has a reinforced boss, so it holds the switch tight).

In the old days, I might've done the install in 3-4 hours, but not having the right supplies (enough wire, connectors, switches) on hand, and in one place, might've helped. I had to splice wires and waterproof the underhood connections, using "stone knives and bearskins" (quote from Star Trek, original series). At least it's done.

Another thing that slowed me down was running a cable (+/- 12v) behind the console from passenger side to driver's side. I popped the carpeted side panels off just enough to slide a 1/2" Pex tube thru, then fed the cable thru to the other side. Worked perfectly. Then I removed the Pex, and reinstalled the panels. I still have about 12" of cable showing in the passenger footwell, but that's only until I replace the missing 12v source there. Meanwhile, I'm using the main ashtray power source (via an add-on USB/12v plug device).

[oldskewel]

LOL I had to look that one up. Glad I did:

https://www.youtube.com/watch?v=F226oWBHvvI

[workingonit]

Felt like heck yesterday, so I didn't even make my final tests of the electric fan conversion until today.

Two problems:

• 1) Finding a true switched power source: The front ashtray power port I was using to provide the 12v switched power never sleeps, like I thought it did. I use the rear console plug-in for trickle charging, leaving the front lighter plug free for powering accessories (and the fan), but I thought it would sleep after 16 minutes as I was counting on. I guess I'll have to use a fuse tap on the sunroof fuse (F58...which I don't want to be usable); I assume the sunroof is switched-power??
  
  
• 2) I guessed wrong about where to put the "push-thru-fins" thermostatic switch. I know that it's supposed to be inserted near the radiator inlet on the top right of my e53, but I chose to insert it on the other side, near the top. My T-switch is a 180F on-165F off pre-set type, but my past experience was that it would turn on too fast in the normal spot (on my racing engines with racing radiators), so I'd end up moving the probe further away from the inlet, to allow the engine to get about 10-20 degrees warmer before the un-adjustable switch would work (and there was already a convenient hole large enough there, anyway).
  
  On this Nissen-branded X5 radiator, it doesn't get warm enough to work at all. I used my Torque Pro app and my 8" tablet to monitor the coolant temperature, which never rose above 194F ( A/C off, electric fan off), idling in park. When I switched on the A/C, the aux. fan lowered the temperature quickly, as did the electric conversion, when manually switched on.
  
  I let it cool down, and tried again, using a meat thermometer and an infrared laser scanner to check temps. The hottest I was able to read via the meat thermometer was 170F near the inlet, 160F where the thermostatic switch is, and the infrared scanner showed 175F when aimed at the bleeder screw on the inlet hose (I assume there's some steam below). I guess I'll have to get an adjustable T-switch like bcredliner suggested, so I can turn it down to meet the lower radiator temperatures that I observed.