as the blotters would be much smaller than the flanges, why remove or perforate them?
What Ray said. The blotters are every bit as big as the aluminum inducer flanges on most 10" wheels. DoALL perforated the rims of the blotters at about the same radius as the holes in the inducers on the wheels they sold directly. As Ray also notes, they provided perforated blotters loose for those that wanted them. To go a little further - the way the inducer is machined, there is a slight groove that is fed by the holes. So the coolant that is induced that far more or less can't escape unless it goes sideways through the wheel. I image that the effect is a little smaller if no blotters are used. but never did any tests. The systems just works pretty well. The big issues on my machine were cleaning out the corrosion in the system form time to time. (the drillings/passages in the head). You do have to run a good filtration system, too. With reasonable flow capacity.
Why couldn’t you use any hub and direct some of the coolant flow to spray on the side of the wheel
You can if you want to.
It won't work near as well.
In case it's not obvious, there is an inducer and a coolant tube to feed it, on both sides of the wheel.
Induced porosity wheels were originally designed to entrain air and cool the work that way, so they could be used on machines that did not have liquid coolant.
I like them either way. With coolant they are even cooler.
However, they do erode faster than say a 8 or even 12 porosity conventional wheel.
Which stands to reason since there is something like (going from faulty memory) 40% less abrasive in some of them.
DoAll's system was designed to work with any typical vitirified wheel.
smt