Oh no! You want to know what the point of all this is. That's a great question but unfortunately a long and convoluted answer!

Here's what it isn't. I'm not trying to help you improve your system, it sounds like it's good already. I'm not trying to be either a basher or fanboy of Grizzly (or Oneida or Clearvue or Jet or Laguna or …), they're all just trying to compete, satisfy their customers and make a buck.

Curiosity is probably the biggest driver. The G0441/2/3 all seem to have performance curves that somewhat outperform their competitor's similarly labeled systems. I used the term “label” because the HP listed as a part of the name of the product just that; it is not a “rating” of the system but rather just the motor rating. What the fan actually demands can be much different.

Most manufacturers “idiot proof” their systems for the hobbyist market. That is, the motor is sized to survive the most extreme hack job someone is likely to do to their system. That means there's margin left in normal operation. That is a prudent thing for the manufacturer to do, customer service is expensive.

Clearvue, for one, goes the other way. They run the motor at it limit, or even slightly past, to squeeze the most performance they can out of single phase motor (5HP is a practical limit, single phase 7.5HP is rare).

It appears that Grizzly does the same with the G0441/2/3. I don't know that for sure so that's why I'm so hungry for the data.

Regarding your velocity questions, I think Bill said 1000CFM to collect the fine dust from a 15” radius sphere. That sphere has a surface area of a little over 8sqft so more like 120fpm velocity for that.

To lift an object you need enough force to both overcome gravity and accelerate the object. The force depends upon the aerodynamic diameter (which depends upon shape) and the density of the object. So an Ebony ball would be a good worst case example.

Also, the kinetic energy of a heavy chip load uses up some of the static pressure leaving less for airspeed. 4000fpm leaves some margin to account for that.