A flow diffuser for vehicles of the type having an engine and an exhaust pipe generally includes a substantially tubular body having an outer surface and a first end configured for attachment to an exhaust pipe. The flow diffuser further includes a diffusion portion including at least one channel having a root end located near the outer surface, an exit port, and a channel axis extending between the root end and the exit port, the channel increasing in flow area along the channel axis to reduce exhaust gas velocity.