Rock on.
Let's start:
We'll average a best/worst case conditions:
A) best case
10HP is produced from 1lb-min of air
15% DT loss
1000whp * 1.15% DT loss / 10 hp per lb-min= 115lb-min Air Req
b) worst case
9HP is produced from 1lb-min of air
18% DT loss
1000whp * 1.18 DT loss / 9 hp per lb-min = 131lb-min Air Req
Averaged, that's an air req of 123lb/min to produce 1000WHP.
We now have a starting point of air mass, all we need to do is calculate fuel mass.
If you re-arrange Air / Fuel = Ratio, you can determine Fuel = Air / Ratio.
We need an air to fuel ratio before we can continue. We know that E85 has a stoic of ~9.8, and we'll pick a safe lambda of .79 (roughly 11.5:1 on a regular gas). Our ratio would then be 9.8 * .79, or 7.74 parts of air to 1 part fuel, 7.74:1 AFR.
Plug and chug, 123lb-min air / 7.74 air/fuel ratio = 15.89lb/min of fuel req.
Since everything in the fuel world is generally done in pounds per hour, convert by multiplying by 60: ~ 954lb/hr of fuel req.
Finally, to convert to volume flow, you need the mass per volume. For E85 (and gas), that's roughly 6.5 lbs per 1 gallon. So, 954lb-hr / 6.5lb-gal equates to ~147 US Gal / hr.
Converted to LPH, ~557LPH.