So I pulled the HDP5 datasheet that showed 200 bar (2900 psi) and 1.1 cm3/camrot flow. I did the math and based on a gasoline density of 6.25 lb/gal, it should support up to E45 with extra boost.
But like I said before, with extra boost and just 93 octane, I was running low on fuel pressure with a lambda below 0.82. How would I know the injectors are at the limit based on datalogging? Do we have specs on the stock injectors?