Injector timing at low engine RPM plays a big roll in response and emissions. Once your about ~ 3500 RPM not very much changes, as you are going to have to be on longer than the intake valve is open anyways. I've attached an excel spreadsheet I wrote that will show you whats happening. If you know your injector pulse width in mS and RPM, you enter those and the calculator will give you crank degrees required to do it.
