Fuel system venting

[dontlifttoshift]

Mustangs are tough. In a perfect world, you would have a vapor dome on the top of the tank and the vent line would be in there.





The vapor dome is higher than the tank can get filled, so that eliminates the need for a fluid/vapor separator. The separators were used on cars when charcoal canisters first came into use. They do exactly what they sound like, allow liquid fuel to escape the tank but prevent it from reaching the charcoal canister. Design wise, they are just like a cheap radiator overflow tank but in reverse. The IIMuch cans do have some capacity to them, but it is not enough in the very specific case of filling the tank full, right to the vent, and then parking the car.

You can:

A. build a separator and plumb that inline between the tank and II Much vent.

Dos. Not fill your tank unless you are planning on driving it.

Triangle. Build a dome on top of your tank

For. vent from the filler neck. Note: not venting the actual tank can affect the filling process.

Personally, if I can, I engineer the fuel tank so that it can not be filled all the way and make sure the vent is on the very top and it usually works. I have built and used separators when plan A doesn't work.