[Jeremy Gonyou]

I think you're trying to hard, Bob.  The way I understand it, Duty cycle is 
simply the injector "on" time (11.6 ms) divided by the time it takes for the 
engine to complete one rev -er, ahem, _cycle_ (34.5 ms)- irregardless of 
injection type, synch or asynch mode, or number of cylinders, yada, yada, 
yada...

That said, I'd like to bashfully change my previous answer from 67% to 33.6% 
Duty Cycle, remembering the old rule that you have 20 ms to play with at 
6000 RPM...

Oh, alright, who's got the real answer?

Jeremy

>This is what I came up with on a v8 tbi setup
>(such as '747):
>
>3475 rpm @ 11.6 msec inj pulse.
>
>-----------
>
>3475rpm / 60 = 57.91 rev's per sec
>
>1 / 57.91 = 0.01726 sec's per rev, or 17.2 milli-sec per rev
>
>v8 = 4 spk's per rev, tbi alternates, so 2 inj cycles
>for each injector per rev.
>
>17.26 / 2 = 8.62 milli-secs between inj cycles.
>
>11.6 / 8.62 = 134% duty cycle.
>
>For a v6, it's 3 sprk's per cycle. For alternate inj firings
>per sprk (or bank fired on every other sprk):
>
>3 / 2 = 1.5 inject cycles per rev.
>
>17.26 / 1.5 = 11.5 milli-secs between inj cycles.
>
>11.6 / 11.5 = 100% duty cycle.
>
>
>Corrections welcome. . .
>
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