Almost all racing which requires refueling uses some form of dry break for the exchange of fuel. These connectors are high flow nozzles which automatically start and stop the flow of fuel. The most basic systems flow well over 8 liters per second. Due to the very high flow venting the fuel cell can be an issue. This is handled in one of a few ways. The most basic method is a large diameter vent hose coming from the fuel cell which leads to a catch can NASCAR uses this method or the next. The next method involves a discriminator valve to separate fuel from vapor. The vapor is then vented leaving the fuel in the cell. The third method, common in Indy, utilizes two dry brakes. One to deliver fuel, and one to capture vapor. Below is a redhead dry break common in NASCAR, ALMS, GT, and several other bodies.
When the nozzle's outer cover makes contact with the female end of the break a male probe is exposed. If everything is lined up the nozzle will open revealing a forcing cone which aids in rapid delivery. As soon as the nozzle is pulled back fuel flow automatically stops.