The Volvo 850/S70 cooling fan is a 2 speed 16 inch diameter fan and wiring it is simple using the Volvo relay. Total cost is about $40.
First get yourself a Volvo 850/S70 fan from the junkyard and don't forget the relay and the mounts for the relays.
I found it best to turn the shroud sideways with the longest side towards the bottom of the stock radiator. The trimming process takes a little time. Basically, you need the total height of the fan and shroud to be less than 5 inches. I went for 4 1/4 inches to make sure you clear the waterpump. I used a circular saw for the big cuts and a hacksaw to do the finer trimming.
In the photo above, you can see that I cut off the bottom of the shroud, then cut about a 2 inch strip which I bolted to the larger piece. This has a lip to engage the original clips and helps give better coverage of the radiator.
Here's my test fitting and there is plenty of clearance from the waterpump.
Next, bend the aluminum at the top of the radiator back towards the engine 90 degrees. Cut the circular portion off the original clips and put them back on the aluminum. Drill corresponding holes through the plastic and install the bolts.
Now, for the wiring:
The large red wire on the right side of the relays goes directly to the battery positive terminal--be sure to fuze this line with a 30 amp fuze.
The middle plug is the Hi/Lo speed wires. They are activated by being connected to ground. The left is the HI and the right is the Low. There are a number of ways to use these, but for now, I have 2 separate switches--one for Hi and one for Low and all they do is connected the leads to ground.
There is a large black wire coming from the fan motor which must be connected to a chassis ground. The other wires remain connected to the existing plugs and the fan.
I cut a section out of the original relay mount and used a band clamp to attach it to the charcoal cannister in front of the power steering pump.
I have sensor from a BMW that will turn the fan on at 91 C, but I have to get a fitting brazed into the metal tube on top of the thermostat housing first. Then, the fan will come on automatically---however only at one speed.
The CFM could not be verified, but on a 105 degree day sitting in my driveway on Low speed with a 180 degree thermostat, the temperature stays in the lower end of normal. Even with the A/C running is stayed south of the mid point on the gauge.