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IDC question

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When datalogging injector duty cylce, do you observe redline duty cycle to determine the remaining capacity or say at full boost?

If you have a data log that includes IDC it should be a fairly easy task to determine what the maximum IDC is under the logged conditions. You will find this will occur at maximum boost and high rpm typically (the injector millisecond pulse width should approximately match your torque curve shape, while the duty cycle will closely resemble the shape of your power curve). Most data analysis software will give you an option to display the minimum, maximum and average of any logged channel to make it easier to define.

So say at 24psi boost my IDC is 65, while at redline, it's 91. My question is do I reference my redline IDC as an indicator I need more fuel for boost? I know 80% duty is the max you want to safely run, but is this 80% at full power(full boost) or at redline when IDC is measured the highest? I will post a datalog when I can.

I would say that you are running out of injector/fuel supply if your IDC is above much more than 80% at its highest point. At this point in your tune you can do two things, increase your ability to deliver fuel, or decrease your demand by reducing/tapering boost pressures. I would recommend that you leave your IDC low enough that it has room to adjust for changes in boost pressure or fuel demand based on IAT/weather changes.