I am starting to setup my staged injector map for another computer and I am using my old PFC map as a reference point. While staged injection can't be adjusted using the FC-Edit, the software does log the MS values for the primary and secondary injectors. I have discarded most of my old logs, but managed to find 3 that go from 2000rpms to 5000+ in boost and vacuum.

It appears that the transition is triggered primarily by the % duty value of the primary injectors rather than by RPM or load. In the logs that I looked at the secondaries came online when the primaries reached ~49% duty.

Is this consistent with what other people have found?

 

YES. Mine use to log at 47% even though the PFC was set at 40%.

 

Great. Thanks Chuck. Interestingly, in the 3 runs I have the transition duty cycle value is always around 40% after the secondaries come online. Maybe that is what that input value represents.

 

To correctly see the transistion, you need to record BASIC to see duty cycle, and ADVANCE to see when INJFRSC goes greater than 0. That is when it happends.

 

I thought I established that in post #1 . That's exactly what I did. Here is one example:

% Duty===RPM===MAP=====InjMSP==InjMSS
43.9 2,920 30 9.12 -
45.9 2,982 32 9.47 -
48.4 3,040 34 9.61 1.89
40.5 3,091 36 8.02 1.89
42.2 3,138 38 8.15 1.89
43.4 3,167 40 8.27 1.92

 

Regardless, the two stock settings for the injectors (Pri/Sec transition (%), Sec transition (ms)) are off in my experience.

Measure when the secondary throttle plates start to open, and then compare to when the secondary injectors start to flow under light load conditions. This is a problem that Mazda did not compensate for, probably due to costs. There is a large gap where both ports are flowing air
but fuel is injected into only one of the air streams causing uneven fuel/air mixtrure.

That is why in the new 16X engine, there is also a direct indection injector.

 

also remember that the Rx-8 is drive-by-wire. I'm not sure if it has the 3 bore TB like the older rotaries but I'm sure it's a lot easier to synchronize fuel flow, port opening, and injector transition when the PCM directly controls the TB.