Replacing the clutch fan with an electric one?

[papasmurf]

Originally Posted by romeokc10

If you do find a suitable replacement what about the belt?

The fan is simply bolted onto the front of the water pump. Taking it off has no bearing on the engine belt or water pump. In fact, by taking the weight off of the front of the water pump, it should promote longevity for the water pump.

Originally Posted by TriX5

4.8is has an e-fan.

Originally Posted by Weasel

I was gonna say the same thing... some V8 E53's have an electronic fan OEM, meaning all the stock parts are available for fitment. Control on the other hand isn't pre-wired or anything so you'd have to wire up the circuit yourself.

Really? I'm going to look into that for sure. That's probably right where the 4.8 gets a bit more power from as well. As for wiring, I was planning on wiring up a relay and having the fan kick on with ignition anyway. It's the safest bet and idiot-proof.

The radiator, if I measured correctly, not counting end tanks, is 23" X 23" wide. The front aux fan, not counting the outer reinforcement, is about 17" diameter. The engine fan, judging from the new shroud I have in my house, is about

So, mathematically:

Radiator frontal area: 529 sq. in.
70% of 529= 370.3 sq. in.

Area of a circle= πR^2= 370.3
R^2= ~118
R= 10.86"
Diameter of properly-sized fan, according to Flex-A-Lite= 21.72"
Diameter of BMW fan= ~18.5"
Difference in area= 370.3 - 269.5 = 100.8 sq. in., or the BMW fan is about 27% smaller than Flex-A-Lite's formula says it should be. This makes sense, given that BMW added an auxiliary fan to compensate under high-heat conditions.

Now as far as current draw, I do not consider this an issue. The Zircon fans draw 10 amps, and as most of us with higher-mileage X's know, having a behemoth water-cooled alternator is more than up to the task of a few extra amps of draw.