My MBC has no markings just a knob(right)+(left)-. Id remove it but i dont have the original equipment. I have ordered a BOV, will that help? I've been giving to MBC quarter turns then taking test drives, it seems that the more i turn the boost down the better the car runs. If anyone can help me out with more info about adjusting both my MBC and soon installed BOV. until then I'll baby the gas pedal. THNX 2 ALL .