A breather catch tank with a 77 x 89mm body, plumbed into the crankcase ventilation circuit. Under sustained load a hard-worked engine pushes oil-laden vapour out of the breathers, and routing that straight back into the intake coats the intercooler, fouls the throttle body and lowers the effective octane of the charge. This tank intercepts the mist, lets it condense and holds it so you can drain it off. It is a standard requirement at most track days and club race meetings, where oil on the circuit is taken seriously. Mount it upright, keep hose runs short and drain it as part of your normal service routine.