Coming from the piston world, I noticed most turbos used on rotaries, stock and aftermarket, have HUGE hotside A/R's. This is, of course, relative to turbochargers used on piston engines, which generally have a smaller hotside paired to a larger compressor. Why is this?

 

Stronger exhaust pulses and more sensitive to exhaust reversion then piston engines.

Being able to run huge turbos is one of the major advantages of the turbo rotary.