E23 M30 Electric Fan conversion

[Mr Project]

Ok, this is my 4th BMW and the 3rd time I've converted one to an electric fan. Nothing against the clutch fans, per se, but it seems almost impossible to find one these days that works for more than a year or so, and that starts getting expensive at $75-85 a pop.

I just bought this E23 a couple of weeks ago (mildly entertaining story here) and the clutch fan was shot, so I needed to do something.

Before shot. You can see this is not quite a stock M30 engine compartment. Cooling is important to me!


Parts:

From Summit Racing, I ordered a fan, temperature sensor, and a relay. Didn't end up needing the relay, so that's $9 you can save. I also ordered some $5 aluminum mounting straps, but couldn't work out a way to use them.

Flex-a-lite 116 2000CFM fan $94
Flex-a-lite 31147 Adjustable fan controller $27

Here's the area after removing the fan and shroud. For reasons explained in my road trip thread, I have a later M30-style water pump and fan on this car, so this was not the bolt-through-fan setup, but rather the 32mm-nut setup.



Here's where I mounted the fan. I bought a 16" fan because I knew I could mount it offset enough to not interfere with the water pump nose. There's only about 3.25" of clearance between the pump nose (with the threads for mounting the 32mm nut) and the radiator. I couldn't find any reasonably-priced and yet 2000-ish CFM fans that would fit in that space, so I went with a 4" thick fan that was small enough to offset to the hot side of the radiator.



Yes, I used the through-radiator mounts that were included with the fan. This is by far not my favorite way to mount an electric fan, but the E23 radiator is oddly-shaped enough that I couldn't come up with an effective way to use straps to mount it to the stock aluminum frame.

On my E34s and an E32 I was able to use a different fan and actually mount it to the shroud, but that wasn't going to work with the reduced clearance of the E23. Here's my E34 setup...which I preferred because it looked cleaner and was easy to remove for access to the front of the engine:



I've had numerous problems with cheap fan controllers in the past. I've actually tapped the water manifolds for thread-in sensors and had those fail and not switch accurately, and have actually had better luck with through-radiator sensors, even though they seem like a compromised approach. This time I went with the flex-a-lite adjustable controller with probe and mounted it near the battery in the front corner of the engine compartment.



Wiring is very simple. Positive terminal of the battery through a 25a fuse to the controller, controller to the + wire on the fan, and the - wire of the fan to ground. I grounded it underneath the fan controller bracket. I didn't use an ignition switched source with this install because I wanted to allow the fan to run after shut-down if the temps were still up a bit.

I mounted the radiator probe several inches down on the radiator on the hot side. I've had issues putting the probe up too high, as sometimes there will be air in the radiator, (especially if you have a failing HG and are consuming a little coolant as the E32 was) and it won't trigger the fan probe to turn the fan on. The worst time to not have a fan is when you're a little low on coolant! The placement here is a little closer to the fan than I would like, due to the offset location of the fan, but it seems to work well so far.



That's it! So far so good, a hard test drive and some adjustments to the temperature controller have it turning on and off appropriately, and it's much quieter than the setup in my E34 so it's not noticeable from inside the car with the windows up. I still need to fabricate a shroud for the passenger side of the radiator, so that will be coming up at some point.

[SamSpade]

Good job! Congrats on the find. No need for the shroud. Your fan is already flush with the radiator so blocking the open area wouldn't really help the fan suck more air through it. In fact, it's better to keep it open so at least you have some air flowing through that area when the car's moving.

I see a turbo in there. Doesn't look like a TCD kit. What is it and how's it running?

[Mr Project]

Thanks, you're probably right about the shroud. I really wish the depth was available to space it back and make a proper shroud, but it is what it is.

It appears to be an old Cartech kit. It's got an RRFPR and a Turbonetics turbo (I think it's a 60-1). Runs well and pulls hard, but I really want to get some gauges on it to see what the A/F ratio really is and how much boost it's making.