Min. injector off time

[gcouger]

-----Original Message-----
From: bruce plecan <nacelp at bright.net>
To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
Date: Tuesday, February 03, 1998 4:09 PM
Subject: Re: Min. injector off time

If you are haveing trouble with not enough fuel at top end would adding
another injector make more sense. That way you could get better low 
end control and have the other injector kick in on high end.

Gordon
Gordon Couger
624 Cheyenne
Stillwater, OK 74075
405 624-2855   GMT -6:00

>Ok let me try again.
>1 cylinder engine SEFI, running max of 6,000 rpm..
>That cylinder would be firing 3000 times a min, or
>50 times a sec..  For a 85% dury cycle it would be 
>on, .017 sec., right?.
>
>Now if that (using round numbers) injector takes 
>.002 sec to open and fire the injector is only
>open .015, and is flowing maybe not 10% less
>but alot less than it's rated amount.  As we spin 
>that eng higher, aren't we actually leaning it out
>more and more since this lag time is decaying the
>actual flow time????...
>     Also even at the 6000 rpm mark we are down
>say 10% from it's rating do to the lag time, isn't
>that throwing things off, for injector sizing??..
>    Now quoting Turbo and High Perf Mag, who
>consulted with RC Eng, as you approach 90
>and more duty cycle the injector Locks open,
>or Locks mid stroke, 1/2 open.
>    So wouldn't larger injectors when in doubt
>be the only route, or at least a rising rate 
>fuel pressure regulator???.
>Sorry for the BW, but I gotta know
>TIA  Bruce
>