Yeah, I removed that airbox from mine too for the same reasons that everyone that had one said it just robbed power. But I always wondered if anyone tried it without the air filter on it. That air filter had the blunt closed-end pointing directly into the airstream, so it was far from a ram air function.

Unfortunately when I redid my plane I utilized the area where the airbox went for other things so it isn't a real simple thing for me to just bolt it on to try it. But I sure would like to have known.

That's why I ran it by you, figuring it would get your engineering brain going and you'd solve the problem for all of us