The ECU has a possibility to up the maximum dutycycle of the injectors, to keep the fueling in order. If this change isn't made, the injectors won't be able to deliver enough fuel for a tuned engine (2.4 intake + good exhaust).
To test the actual dutycycle of the injectors, we connected a scope to my car.
The scope is connected to a notebook where the software shows the information. With special clamps the scope is connected to one of the injectors.
With a low engine load, the scope shows the following picture.
With high load and high RPM's we got the results below.
According to the scope the dutycycle is around 93%. Repeating this test gave values between 90% and 93%. These values are only seen at high RPM, so the injectors aren't run very long at these dutycycles.
In the piece I wrote on injectors there is information on the relation between dutycycle, injector size and maximum power.
Based on thie information the following formula can be used:
Where:
