OK, I think I get where you're coming from. You're coming from an industrial take and calling a Lysholm type a compressor because it internally compresses the air and a roots type a "blower" because it has no internal compression?
That makes sense actually as we use large (think 10/71 size as I have no other frame of reference) superchargers to evacuate bullet fragments from our range traps. So I'm thinking the suction that they can produce must be pretty good along with the volume moved.
Sorry OD, I wasn't thinking about industrial apps.
In answer to the Toyota question; it's a modified, or twisted rotor type, roots. Here are a couple of pics of the rotors. You can see that the compression would be external, a byproduct of moving more air.
