OK, here we go.

I'll be uploading this about 20 minutes at a time, since that's about all the longer I can sit at a time.

It seems that the "Taurus 3.8" fan came in many varieties, and the motors from several manufacturers over the years, with different specs (speed and efficiency).

The 94-97 Thunderbird and Cougar XR7: All engines (3.8, 3.8SC, 4.6), used a 60 amp fuse and dual relays to power a 16" fan with a low and high setting. It seems to be using a blade configuration that is different than the Taurus (closer to, but different than, the Mark 8) but a motor that is one of the various Taurus units.

The 90-95 Taurus and Sable, and 90-94 Continental: 3.8 engine, used a 50 amp fuse and dual relays to power a 16" fan with a low and high setting. This configuration seems to be running about 26 amps on low (32 at start) and 29 amps on high (45 at start)...OR...running about 34 amps on high at 3,750 CFM. Or 3,800 CFM. Or 4,000 CFM. Or 4,500 CHM. Or 4,800 CFM. Or 3,500 CFM.

However, some sources claim that it takes 100 amps to start the high speed.

It seems that this unit runs about 2,500 CFM on the low speed. Or 2,900 CFM.

The 93-96 Mark 8: All engines (4.6), used a 40 amp fuse and a single relay to power an 18" fan with a low and high setting. This one is interesting, since it uses the smallest amp fuse, but has the most powerful motor. It used the high speed with a variable control relay module (VCRM) to dynamically vary the speed. This would be consistent with the idea that the Mark 8 fan has a stronger motor and larger diameter, but because of the noise-reducing blade pitch, has the same CFM as other fan combinations.

This configuration seems to be running about 28 amps on low (40 at start) and 35 amps on high (53 at start)....OR...running about 28 amps on high at 4,300 CFM. Or 4,500 CFM. Or 4,800 CFM. Or 5,000 CFM.

Because it uses a variable relay, the 53 amp high start would never take place, as the fan would already be running. Perhaps that's how they can get away with the 40 amp fuse. And perhaps a DCC would allow for the same.

ôI just laugh at myself now when I see how seamlessly the DC controller works. Not only is the control much better (on mine within 2 or 3 degrees), the fans don't work near as hard. They ease on as the current ramps up, so I don't have the short-term 80-90A hitting the system with both fans coming on full. In fact, I went back and installled the indicator light Brian sells because I couldn't even tell they were coming on at all so smooth and quiet is the operation. Now I'm mesmerized watching the light change colors from green to yellow to orange to red as the fans speed up and down keeping the engine cool. Pretty amazing stuff. And, it saves wear and tear on both alternator and the fan motors. It really is a better mousetrap with no downside.ö

Many folks talk about the need for an upgraded alternator, especially with the 100 amp start-up story. I'm not the smartest guy in town, but it seems to me that the 100 amps (if it even actually needs that) could come from the battery, since it's only for a moment, and the steady running high fan would only draw a constant 35 amps. Does an additional 35 amps MAX (that's for the high speed) really require an alternator upgrade?