DFI, Batch Fire, and other myths

[Mike Brown]

Gary Derian wrote:
> 
> Recent research on fuel droplet sizes has shown that injecting fuel onto a
> closed intake valve, then letting a shot of exhaust hit it when the valve
> opens (reversion) produces better and smaller droplets than the injector
> itself can generate.  See the SAE Journal from a month or two ago.
> 
> With this info, SFI could be used to insure that all the fuel is injected
> while the valve is closed, not open.  How are the SFI systems actually
> timed?
> 
> Gary Derian <gderian at cybergate.net>

Gary,
	On the Edelbrock ProFlow it is a function of RPM only.  Not much
resolution in the system so it can only advance the injector timing in
90 degree (crank degrees) chunks.  The break-points seem to be set up so
that most of the time the injector has finished firing before the intake
opens.  Some situations, like low rpm and high load it will still be
spraying while the valve is opening.

Mike