On my old setup with the helix I pushed it to 33 psi on a gen 2 6266 and thats as far as I would go because rail pressure was like 1700-1800 psi. I have a couple guys that wanna be in the 650-700 hp range and I figured this would be something right in that area.Haven't established the ceiling yet, at 670 whp we were still holding 3k psi at redline, but that was stock motor and didn't want to push further. Have a guy in Florida with a big single who wants to crack 7 DI only and just got mailed all the parts/supporting mods to do so. Ethanol mixtures will be the same ratio as stock HPFP ceilings on E85/E50/E30 mixes, but really too much goes into a tune to accurately project until someone just plain does it. Put another way, how much power do you want to make on DI only?
I will say this, LPFP seems to go significantly further when you are DI only. Usually we rate a single shot 274 (standard F90000274, often referred to as a 450 in the community) at mid 500's to just under 600 whp worth of flow, but we easily crested 600 with plenty of LPFP in the tank. Went double on the car after mid 6's no prob. A great combo is a 295 (~30% increase over 274) single shot with the POD. Lots of flow, easy, simple, DME control over everything. Doubleshot 274/274, 295/274, or 295/285 after that.