with help of @960
, we've figured out what the stock injector calibration looks like.
The parameter KRKATE defines the injector flow at a particular reference pressure, which in this case comes out to 1214 cc/min at 10 MPa (100 bar) fuel pressure.
The table labeled Korrektur bei variablem Kraftstoffdruck (correction for variable fuel pressure) contains a mapping from fuel pressure (MPa) to reciprocal correction factor from the reference flow. So at 10MPa it indicates 1.0 (no correction), and at 3MPa it indicates 1.826, which means the flow is 54.8% of the reference flow, so 665 cc/min.
With some math in excel, we can confirm a few things:
1. These injectors are identical to the injectors in the 2013 Ford Focus ST (that I used to own)
2. The curve follows a perfect square root vs. pressure relationship, as is expected. Flow thru an orifice is proportional to the square root of the pressure.
3. rusEfi doesn't need a full fuel pressure vs. flow table: we can simply use a reference pressure/flow, and convert on the fly using sqrt.