Originally Posted by plat27265

Bosch is a fuel pump manufacturer. By design, they would know the conditions that will jeopardize its life. Concerning the scale, they (the pump manufacturer) cannot tell because car manufacturers design fuel tanks differently from one another. There is no one shape fits all kind of scenario.

The Owners Manual of my '16 S5 contains warnings against running the gas tank until its completely dry which is not the case here. However, it does say that once the 'Please Refuel' indicator lights up for the very first time, there is still around 2.1 to 2.4 gallons or 7 to 9 liters of fuel left in the tank. This is for the B8.5 A5/S5. Your car's owners manual should have similar info.

I think the key here is to never have to see the 'Please Refuel' indicator light to remind you to fuel up. Be proactive by planning ahead and fuel up whenever you are close to Empty or when the gas gauge is in the red zone. Especially on long trips where the next gas station is miles away and you only have 3 gallons left to spare just because you procrastinated by skipping the last gas station on your way to your destination.

Originally Posted by morris39

I agree. The point of my experiment was to find out the possibilities in event of an unavoidable low fuel condition. The real decision point is a balance of minimizing fueling time vs need to to be constantly on notice or worse, one totally dry event would likely wipe out any convenience gains. I my case for local trips I refuel at around 15 % of tank volume or about the last fuel guage line and usually before the warning comes on. On longer trips minimizing stops governs so usually more left in tank. I should have emphasized that this was strictly an experiment. I also should have resisted the urge to comment on the uncommon pride in common knowledge like the MR4D dude.