It depends on where the airflow comes from.
On a modern 808, you can file down the slots at the base of the cartomizer and enlarge the holes uner the
threads on the battery connection to loosen the draw.
Similarly with a 510, you can file down the slots above the battery connection and enlarge the holes at the base of the atomizer.
On an eRoll, I'm not sure. I haven't used one yet, but I'd imagine you could enlarge the air hole on the side of the battery. You'd probably want to file that down by hand.
Good luck.
