One thing I came across when calculating different inputs into my spreadsheet is in todays rules for 2014 a 6 cylinder verses a 4 cylinder.
At 10500rpm delivering 100kg/hr a 6 cylinder using DI will only have 2.857 m/s to deliver fuel during the compression stroke or 180* crank rotation. With a 235 cc/min PI of today you would have a pulse width of 1.79 giving you a duty cycle of 62.5%.
At 10500rpm delivering 100kg/hr a 4 cylinder using DI will only have 2.857 m/s to deliver fuel during the compression stroke or 180* crank rotation. With a 235 cc/min PI of today you would have a pulse width of 2.68 giving you a duty cycle of 93.8%
IMO I believe this was the main reason they went with the 6 cylinder format. It was more of a way to make use of today's DI at full max power. I personally think the 4pot is a better engine to go with but I don't think today's DI is capable yet.
Now my example of above is using a well know PI injector that is proven to deliver 235 cc/min. The DI injectors will flow more, but keep in mind there will be injector dead time and some valve overlap for cooling and clean charge they can't use the full 2.857 m/s or 180* crank rotation to deliver fuel. So this will shorten the time for fuel delivery.
m/s=milliseconds