Im guessing increased air velocity, but is there a certain size difference it needs? For example the itr is 66-62. Would it not be a good idea to make it 66-65, but thats not very tapered. Im looking for a good size for my b16 w/cams but dont wanna go too big. I wanna make it the same size as the IM inlet, which will be 64 or 65.

 

If you want taper and a 65 mm plate you have to go billet. The honda throttle body only has so much meat. I do the taper throttle body for customers with mild applications and Im a huge fan of it. Throttle response and bottom end is not effected like the larger non tapered throttle bodies.

 

yea but how much of a difference(numbers wise) do they need to be? What about a 66-64(plate)?