You will never see 300psi, nor will 2x1000cc nozzles be as efficient as smaller nozzles. Well other than when the pump is pumping against the closed valve and if the pump has been adjusted to see a higher pressure.
In fact, with nozzles that large I'd be surprised if you ever see much over 100psi. The pumps simply do not flow what the suppliers claim, and any pressure claims are against a dead head.
I've tested the AEM big pump under load and in the real world at pressures required....realistically they're only around a 1200-1300cc pump, and that was with a quoted 1600cc worth of nozzle...and tested not fighting against boost pressure which would reduce flow further.
Even with only a 600cc nozzle...my factory set 200psi pump, could never create 200psi.
With 1600cc worth of nozzle, in the car, in real world use max pressure I see is around 140psi....so if using say 40psi boost, that's now only 100psi of effective pressure to inject, so even less flow.
But stick a pressure sensor on the line and log it for yourself and use this to control any fuel/spark adjustments, rather than what you're currently doing which offers no failsafe. It's a cheap and easy way to monitor what the system is doing, and could be an eye opener.
It's a pity nobody seems to have done much testing on the various systems and pumps out there to prove or disprove the suppliers claims.
