Abstract: An aluminum pipe according to the present invention is used in forming a plurality of bulged portions on the peripheral wall thereof. At the same time by bulging has been so refined as to exhibit an elongation of at least 40% and a recrystallization texture of up to 60 .mu.m in grain size during bulging. The aluminum pipe to be bulged is produced by a process characterized by drawing an extruded aluminum pipe at a cold working ratio of at least 40%, and thereafter annealing the drawn pipe at a temperature of 350.degree. to 420.degree. C., whereby the pipe is refined to exhibit the specified elongation and recrystallization texture.

Abstract: An intake manifold adapter comprising an adaper body made of aluminum and having a gas channel adapted to communicate at its one end with the outlet of a throttle body for holding an air cleaner in communication with an intake manifold and at the other end thereof with the inlet of the manifold, and an exhaust gas inlet pipe having an aluminum portion at its one end and a stainless steel portion secured thereto and providing the other end of the pipe, the inlet pipe being fixed to the adapter body by the aluminum portion being metallurgically joined to the body, the stainless steel portion providing a joint for a pipe for returning the exhaust gas from an engine to the manifold.

Abstract: A process for producing an intake manifold having a main pipe made of wrought aluminum material and having an open end, a closed end opposite to the open end, a plurality of holes formed in its peripheral wall and outward tubular projections integral with the peripheral wall and each formed around each of the holes, and a plurality of branch pipes made of wrought aluminum material and each having one end fitting in and joined to each of the tubular projections. The manifold is smooth-surfaced in its interior, diminished in resistance to air and improved in air intake efficiency. The manifold requires no finishing procedure unlike those prepared by casting.

Abstract: An intake manifold comprising a main pipe made of wrought aluminum material and having an open end, a closed end opposite to the open end, a plurality of holes formed in its peripheral wall and outward tubular projections integral with the peripheral wall and each formed around each of the holes, and a plurality of branch pipes made of wrought aluminum material and each having one end fitting in and joined to each of the tubular projections. The manifold is smooth-surfaced in its interior, diminished in resistance to air and improved in air intake efficiency. The manifold requires no finishing procedure unlike those prepared by casting.

Abstract: A fuel pipe device for motor vehicles comprising a pipe main body having a plurality of holes formed in its peripheral wall and outward tubular projections each formed around each of the holes integrally with the wall for connecting branch pipes to the pipe main body. The device is produced by a process comprising bulging the peripheral wall of a pipe blank at each of the portions thereof to be connected to the branch pipes to form a tubular protrusion having a closed end, forming a hole in the center of the end closing wall of the protrusion, and bending the remaining portion of the end closing wall around the hole outward by burring flush with the peripheral wall of the protrusion to form the tubular projection. Alternatively, the device is produced by a process comprising forming a hole in a pipe blank at each of the portions thereof to be connected to the branch pipes, and bending the hole-defining portion of the blank outward by burring to form the projection.