I want to build a new Y pipe for my crown motor, but unclear as how an original lexus Y pipe is constructed to give it good flow. I am going to use the original crown headers despite their bad design at this stage, having to move oil filters etc to clear rush headers maybe over kill for the increase in performance gained. I plan to use 2" mandrel bent pipe for the system with the 2.5" Y pipe section just behind the auto.There are no cats in the system I can't remember if the crown actually had one but I guess it would have been installed further down the system after the pipes merge. So I guess I am asking is there a particular angle that the Y pipe needs to come together or way it is constructed. Has PBrady done a follow up on his investigations into building a better Y pipe. thanks for any advice.