what is a secondary intake runner?

 

It allows a large volume of air to be sucked into the engine, increasing high-end horsepower (high rpm's).

 

An intake manifold with secondaries has 8 runners total, with 4 of those containing little throttle plates. You only have 4 smaller holes at lower rpms for better power down low, then at higher rpms, the plates open to let more air in. Works well with VTEC

 

any 1 have a pic?