THE DESIGN PROCESS
When designing your tank, there are a few little tricks that will ensure that it functions properly. Sadly, this will require you to betray your teenage self and actually use some of that maths you told your teacher you’d never use in real life.
First, you will need to work out the shape. There is no real performance difference whether it’s round or square; it comes down to personal preference for aesthetics or packaging. Every other custom tank in our project car is a cylinder, so we decide to continue this theme. We want around 10 litres, which is massive, but gives us a litre extra overall capacity. The other design restriction we set is having a 180mm diameter, simply because that’s what size tube we found in the workshop and we wanted to avoid having to form a bespoke cylinder.
To work out the required height to achieve our 10 litre goal is where that maths kicks in: Π (3.14) x radius (cm) x radius (cm) x height (cm) will give you the volume. Punching in a height of 40cm gives us the calculation 9cm x 9cm x 3.14 = 10.1 litres, which is close enough to our 10-litre goal. Our final shape will also have a small sump on the bottom that our pumps screw on to, and also a sump on the top for the feed and return to mount to — so the overall capacity is closer to 10.3 litres.
The final design consideration is how the tank will mount in the car. Ours will sit on the base, welded to the fueltank cradle, and, for simplicity, we are going to use a large bolt-on pipe shoe, which is essentially a hose clamp with a mounting base attached.