I was looking at the effect of moving the staging bar up with different sized injectors. Knowing that its possible to max out the injectors, or exceed a safe duty cycle. Knowing what the duty cycle will be based on rpm and pulse width seems like it would be helpfull in knowing if I am at or near max duty cycle.

Then I came across this calculator: http://www.stealth316.com/2-calc-idc.htm

CAUTION read the waring.

warning: whatever duty cyle it shows for a given rpm double it, if it shows 50%, for a rotary its really at 100% and so forth. This is because its calcuating duty cycle based on rpm and pulse width and not actually measiring it. Duty cycle means the same thing for a piston engine as it does for a rotary, (i.e., 100% duty cycle means the injector does not close) however whith a piston engine the Otto cycle takes two revolutions per pulse instead of one.

So what does this do for you, well take a given rpm, say 6k, run the calculation, and you will know that you can't exceed 4.5MS if you want to stay below 85% duty cycle.