Hydra EMS has started working on the direct injection code for me after analyzing the OEM scopes of the DI system. It's very interesting and enlightening and we'll have no problems adapting this version of D4S system into the current Hydra EMS hardware.
We will be adopting the OEM direct injection and port injection strategy mostly but we are going to leave DI timing tunable so should I find benefit as we boost this engine we'll have that option to change timing based on load.
Based on the direct injector pulse width at idle I'm going to estimate the OEM direct injector flow is around 400-450cc. As RPM gets towards redline and both the port and DI injectors are firing the total pulse width would suggest less flow however than the sum of both injection systems. Regardless there seems to be plenty of injector pulse width left to play with between the two systems.
The torque drop off in the 4k rpm range can be seen in the injector pulse width scopes also. Clearly a VE drop off there but that will tune out nicely with a turbocharger system
As it sits I think we can get away with some low boost turbocharger systems on the OEM fuel setup but at higher boost levels at least a rising rate fuel pressure regulator is going to be needed for the port injector system.
Thanks,
Phil Grabow