Performance 6.5 Injectors

[gmctd]

Except that the stronger spring delays injection while the pump is still building pressure to 'pop' that spring.

The volume between 1700psi and 2200psi is then lost - PCM doesn't know about that and doesn't compensate with the Fuel Solenoid - it is a fixed beginning\variable ending injection system.

Beginning of injection event, PCM closes FS, rollers are rising on the ramp, plungers are pumping their specific volume against the closed injector, building pressure.

At 1700psi inj pressure, injected volume is from that point on the ramp until PCM opens the FS at some point further up the ramp, ending injection.

At 2200psi, the rollers are further up the ramp when injection begins, but PCM still opens the FS at the same point further up the ramp.

PCM can attempt to correct for that at idle with the Cylinder Balance routines, but that's only at idle, used to maintain idle rpm in Neutral, Drive, A\C on or off or cycling, headlites on or off, anything that varies the load on the engine.

Even at that, hi-pop hi-flow injectors do not idle as smoothly as the standard versions, nor is idle speed stable, and can vary by 100rpm low.

Those Cyl Bal routines are not used off-idle.

The Injection Fuel Rate seen on the scanner is not measured - it is calculated, based on conditions with oem standard lo-pop injectors, spec'ed by engineering to ensure the camring and rollers would survive thru the warranty period, while still giving adequate spray pattern for economy.

'Course - I'm talking EFI DS4, you're talking mechanical injection DB2.....period.......and, as we all know, turning up the fuel on the DB2 effects the fuel rate from idle to full throttle, right?

That's why I would like to see dyno results compared to scanned data.