Quote:

*GR said:*

If sloshing is a problem, the tanks have baffles. These are simple plates that stop the fuel surging across the width of the tank. Some cars don't need them and I'm not sure about Porsche. However, 30-40 litres of fuel surging across the car in a high g manoeuvre would probably be felt by the driver (soon after the turn is initiated) so I would guess the Porsche tank does have baffles.

An interesting question.

Since this is the Boxster Board, let's base our thoughts on the Boxster:

- This car's fuel tank is a plastic blow-moulding, so it is a one-piece moulding with a narrow neck, like a detergent bottle

, so no access to install baffles as could be done with a pressed steel tank made of two shells welded together.

- When tank is full, there is no room for fuel to slosh around, so no problem.

- When tank is almost empty, the weight of the remaining fuel which could slosh around is negligible, so no problem.

- Let's assume that worst case is when tank is half full, therefore containing 30 liters of fuel, which would weigh roughly 24 kilograms. Imagine a 1.0 g left hand turn on road tires (the highest lateral acceleration you are likely to achieve on normal asphalt). The half of the fuel (12 kg) on the left-hand side of the tank will tend to slosh over to the right hand side. The fuel surface in the tank will be at a 45 degree angle to the ground, due to 1.0 g (gravity) acting downwards and 1.0 g lateral acceleration due to cornering. So only half of the 12 kg (= 6 kg) will slosh over to the right hand side of the tank).

Assuming 600 kg of the Boxster's total weight of roughly 1300 kg act on front wheels, the "normal" load per front wheel would be 300 kg per side. Assuming that full weight transfer of fuel acts only on the front wheels, because tank is ahead of center of gravity of the car, then the weight transfer of fuel to the right hand wheel would increase wheel loading from 300 to 306 kg.

I think it is safe to assume that the weight transfer of 6 kg due to fuel sloshing around in the tank would hardly be noticeable compared to the other effects on wheel loads arising during hard cornering.

The above "analysis" includes several assumptions and approximations for the sake of illustration, but I think the conclusion will not be too far from the truth.