I've tuned a few Zr1s and never ran into an issue like this. The fuel pressure dips at 4k no matter how I have the high flow mode kick in. If I set it before or after where the drop is happening the pressure still drops. I've adjusted just about everything I can think of. Can someone take a look and see if I'm missing something? Bolt on ZR1 making about 700rwhp.
Pump cuts out and builds back up after 4k. HAROON.019.hptHAROON.019STREETPULL.hpl