Get a tight bore barrel and rhop.
A standard hop up nub has to pinch the bb really hard, and hold onto it for quite a while, causing wasted air to go right past the bb for a bit.
Same thing with your barrel, if the bb is loose, air goes right by it, wasting quite a bit. Pick up a Prometheus 6.03
What is your idea of low air consumption? What tank are you using and how many shots are you getting out of it?