Direct Injection

[Dave Williams]

-> valve opens.  On SEFI when does the fuel inject?

 It doesn't really matter.  The intake port has plenty of turbulence.

 Most port injection systems are batched; for the few that are truly
"sequential", the injector timing can be played with at idle for
smoothness or emissions, but at quarter-power you'll be injecting
through the whole intake stroke anyway; at full throttle the injector
will be on most of the 720 degree cycle.