Are you dumping liquid or smelling gas after the left turn? If you don't have an EVAP system, the Tee to the vent is pretty low in the instructions. You could pool fuel up the filler neck, and force gas into the vent system. Since the cars suck exhaust and engine heat back into the cabin, it does not take much to smell. If you have liquid loss, I would check for leaks on the filler neck hose and vent clamps. The build instructions tell you to hammer out the restriction in the neck, but as I was starting to bend the lip the cap sits on, I left it there with no ill effects so far. The cap os probably fine, the filler neck might be dented and no longer flat. If that is the case, Rockauto sells new ones.
Joe