Boost pressure control valve
hi lads a mate of mime has got to swop out his Boost pressure control valve......amal valve he has a big turbo escort cosworth . the thing is he has a black one on his car and he has just got his hands on 4 new ones 2 black and 2 brown is there any diforenc in them and should any of the ports have a restrickter in them and if so which ones thanks for your help