Viking beat me to it. Couple guys running blowers on the street around have had trouble with excesive crankcase pressure and have gone to the evacuation system shown with good results. The angled pipes are welded into the headers and exhaust flow creates a vacuum the pulls the pressure out of the crankcase. The round fixtures are one way valves that protect from back fires blowing back into the crankcase.

My other suggestion is to call B&M, it's their blower, I bet they have trouble shot a few systems before.

Pat