right, im gonna run these throttle bodies on a zeec engine, im getting to stage where im thinking about manifolds, but i cant decide what to do about the openings of the TBs. see pic:



as you can see if i made the manifold the same diameter as the outside of the TB housing, thered be a massive step down from the throttle into the inlet, which would obviously be shit for airflow as itd create a turbulent area around the lip as the airflow spilled over the edges into the inlet.

i dont really know what the best way to get around this problem. im thinking im either going to have to machine down the end of the TBs to make a smooth transition into the inlet, or make the inlet the same size as the throttle (38mm) and figure out a way of sealing the throttle bodies to the inlet.

what do you think? im leaning towards machining the TBs as itd be easier but im not really sure on the effects of making the TBs into a venturi would be on airflow, although im fairly sure itd be good for fuel atomisation? (although its just an guess more than an informed judgement! )

im guessing again that keeping the inlet 38mm right into the head would posibly be best for torque but im not 100% sure.

help please!