Quote Originally Posted by Fox351 View Post
Understood. I haven't seen a "primary" injector on the obx itb. That seems to be the only one. I can't imagine that at idle and low throttle that would be the ideal spray pattern due to the interference with the butterflies. You have built more motors than I have so I will take your word for it. I was just wondering if that is the best spray pattern why would Jenvey, Kinsler, and TWM have them with the fuel injectors behind the butterflies? I can completely understand at WOT that with the injectors infront of the butterflies it would allow more time for atomization of the fuel and air mixture but at idle it leaves no room and puts a plate in front of it for the fuel to liquidize on. As far as dollar per horse power I would agree that they are expensive. I can't disagree with that. I was asking the question on a more engineering point of view instead of engine building advice.
gotcha, what they arent showing you is the injectors above the throttle plates are secondary meaning they are on a switch, they only turn on under WOT. you have another set of injectors (like normal) for idle and low rpm , closed throttle applications.

like so