Explaination on injector duty / milliseconds
 

Can someone tell me how does milliseconds relate to injector duty.

How do I know what duty cycle I am at if duty is logged as milliseconds.

What is a maximum safe injector duty in milliseconds to be at?

The Maximum Injector pulse width will reduce as RPM's increase, as the time the rotor face spends in induction phase will be shorter.

You should be able to work out for what portion of the rotation the engine is drawing in air / fuel - so the time it takes for one rotor face to swing past the intake ports. That would be your maximum injector pulse.

You'll find port timing info in the Service Manuals - but if you're engine is ported then these will have changed ;)

You need to find out what values you have currently set - if you need to get more fuel in and are already maxed out on pulse width - then you need more or bigger injectors.

Injector duty cycle is simply how long your injectors are open vs. the amount of available on time.

Once you have that information, your duty cycle would be easy enough to calculate.
Lets say your intake port will be open for 10 milliseconds, and your computer has determined that the injector needs to be open for 9 milliseconds. You would then be running at 90% duty cycle. Which is safe to do with low impedance ( or peak and hold ) injectors but not safe on high impedance ( or saturated ) injectors because they need more current to stay open and can burn out the solenoid.

Typically people don't go through the calculations to determine whether they are close to max duty cycle or not. During tuning if they are adding fuel in their maps and the A/F ratio goes nowhere, its a good sign that you have run the injectors too far and bigger ones are needed.

You are able to log injector pulse time in ms. , but I am at a loss as to how you would calculate your available on time. As prof said as your engine speed increases and the rotor moves by faster, the available on time will shrink.