Verus Engineering Fuel Starvation Flapper - FRS/BRZ/86
Verus Engineering Fuel Starvation Flapper. In some cases on high-speed cornering, your vehicle can experience fuel starvation. Verus Engineering has designed a simple and effective fix to the fuel starvation issue by designing a purpose-built door that allows fuel in and keeps it from going back out during left turns.
Note that this is not a replacement for a surge tank and will not allow you to run the tank dry. This is a solution to fix the fuel basket from draining during left-hand turns, and will allow end users to run less fuel before fuel starvation will occur.
Here are more details:
Note that the 2015+ STI models come with a similar flapper door from the factory.