[ふっとばす, futtobasu] (v5s) (1) to blow off something (strongly); (2) to blow off one's worries; to brush away one's worries; (3) to accomplish a task very rapidly; (4) to drive (a car) at full speed
[ぶっとばす, buttobasu] (v5s, vt) (1) to strike (as to send flying); to beat; to knock; (2) to jump with force; to leap; (3) to accomplish a task very rapidly; (4) to drive at full speed (e.g. a car)