Custom silicone reducer hoses or custom silicone reducers provide for a transition between different sizes of engine pipes or tubes. Consequently, one end of the reducer is larger than the other. Dimensional specifications include hose inside diameter (ID), hose outside diameter (OD), and length. Applications include connecting different sizes of intercooler, turbocharger, supercharger, and intake components. Reducer hoses are also used to join the intake pipe to a throttle body assembly, an air metering assembly, or custom compressor.