Injector time is measured with Duty Cycle. My Buick with 232* of duration at 0.050" has the intake valves open about 32% of the time. So once the duty cycle goes over 32% the injector is spraying at a closed valve waiting for it to open. Once you are at 50% duty cycle, the injectors are open half of any measured time. In one second the injector is open .5 of a second, in one minute the injector was open 30 seconds of that minute. So the problem becomes, when injector 3 starts spraying, cylinder 4's intake valve is open and sucking the first part of that fuel and when intake valve 3 finally opens again it gets a lean charge low on fuel because cylinder 4 just ran rich with part of 3's fuel charge.
You are not going to get injectors big enough to escape the duty cycle scavenging issues. You will run into the issue anytime over around 32%.
**Originally I wrote 8%, I got the 8% number from the amount of time the intake valve is open AFTER the exhaust valve has closed on the overlap period. Which is determined by the LSA.
