I read on a forum somewhere that the stock ECU can adjust for about a 20% larger fuel injector and still perform optimally. Is this true? Are there any injectors you can put on to get gain without a reflash?
That is a negative. The ECU is completely unaware of any changes without a tune. You’d be increasing the size of the injector with the same injector duty cycle and fuel map. Stock injectors wouldn’t even max out with I/h/e.