Does anyone know how much rpm effects parasitic loss in Bravo or IMCO style drives? I remember reading that a bravo style drive robs a lot of horse power above 5500 rpm? There are a few guys that say you should not spin them any faster then 5500 rpm. We have been spinning them faster with no issues but wondering the efficiency loss comparing to doing gear change.

I have nothing of value to add other than "parasitic loss" is the term you're looking for.

Thank you! I edited my poor grammar.