I use individual cylinder trims for fuel and ignition on my engine (AEM EMS series 1), and I swear by it.
However, I'm using mine to counter-act the tendency of cylinder 3 to run "hot", and cylinders 2 and 4 to run relatively "normal", and cylinder 1 to run "cool".
I have +4% max extra fuel (based on RPM) for cylinder 3, and a maximum of +2% fuel for cylinders 2 and 4.
I have a max ignition retard of 2.5 degrees (based on RPM) for cylinder 3, and a max retard of 1.5 degrees for cylinders 2 and 4.
Now, your idea of counteracting the small variance of injector flow with individual fuel trims seems like a viable option even without per-cylinder O2 sensors. You could go off the flow chart data you have if it is comprehensive enough. If it were me, I would adjust the trims to balance out the fuel, and then I would adjust the trims on top of that to adjust for the per-cylinder behavior of our engine.
However, if you don't want to get that complex, I would simply do what I've done and ignore trying to balance out the injectors, since they are off by less than 1% each which is less significant than the +4% fuel you should be adding to cylinder 3.
Last edited by BenFenner
on 2015-09-10
at 14-05-09.