[Vanner]

I would think a SMALLER bore throttle body would help at moderate throttle positions, given that the air restriction would then "be" at the bore and allow the throttle plate to open up more for a given demand. Nascarnation nailed it: your restriction is at the throttle plate unless the plate is open.

jonr touched on this: for WOT there is no throttle plate and fuel economy should increase with a big bore. Great.

I see this argument as in a similar vane to CAIs, they say if you can reduce intake restrictions the engine doesn't have to "work as hard" (whatever that means) to cruise at some speed. Seems like rubbish, the throttle plate just chokes off whatever progress you make upwind.

Anecdotal evidence is evidence, I know, but there a hundred factors that go into fuel economy. And no one yet has installed a throttle body trying to save money.