Abstract: An intake tubing includes a tubular member having a number of helical protuberances and a number of helical grooves formed in an inner peripheral surface, an inlet end for receiving fluid, and an outlet end for coupling to an engine. The helical protuberances and the helical grooves of the tubular member may guide the fluid to flow through the tubular member in great speed and to increase power of the engine when the fluid flows quickly toward the inlet end of the tubular member, and to generate eddy current and to lower the flowing speed of the fluid when the fluid flows slowly toward the inlet end of the tubular member, in order to economize fuel or fluid.