the stock tank has a hump in the center where the driveshaft passes through. Fuel pump is on one side and a vaccum type pickup is on the other side, that runs off suction on the fuel pump to lift fuel from the other side of the hump and dump it into the pump side. At high power levels, if any air gets sucked into the pump or worse it sloshes away from the pump and starves it, the motor is toast. So with the dumpy oem tank design, you better keep that tank FULL, half empty and your hitting that threshold where the hump is in the way… less and you have even more issues, the pump isnt sumped or anything to keep it wet at all times with fuel sloshing around. Also, the stock sending unit for the level from the AWD tank doesnt work for some reason… its only 3 wires, i am confidant I didnt wire it up wrong, so hes flying blind at the moment anyway.
Fuel cell is plastic for e85 so we dont need to get an aluminum one anodized, its just easier this way. Its sumped out the back/bottom so it should feed the outlet very well when it has adiquate fuel inside it. Has an aftermarket sending unit in it and i will put a standalone level gauge in the car to keep an eye on it. Also the return is already AN and will just be extended and attached to the top of the tank, vent line attached to the tank and sent out of the trunk. We are also bumping the feed from -6 to -10 pump to reg to rail.
Its just alot easier solution with less variables than dealing with the stock dumpy tank, pump basket, lift pump thing and sending unit.