Because someone asked.
There are three physical injectors but there are actually only two "logical" injectors, one big one small.
The two "physical" injectors in the B ports are there for symmetry of fuel distribution and are fired together as one Logical injector.
I use three physical 124g/min injectors but the EFI CPU sees only two logical injectors, a 124g/min slow speed injector and one 248g/min high speed injector.
In broad terms, because there is much the same amount of air consumed per revolution. Both 124 and 248 Logical injectors each deliver much the same amount of fuel per revolution.
Attachment 332298
Both 124 and 248 injectors deliver much the same amount of fuel per revolution.
Because the 124g/min injector at lower speed has 10ms to do the job.
And the 248g/min injector at higher speed only has 5ms to do the job so needs to be twice as big.
Time available dictates the relative injector sizes.
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