There are several scenarios that would require you to upgrade an existing fuel system. An engine upgrade is a logical situation. If you are installing a new engine that is packing a bunch more horses under the hood, then you better make sure you have enough fuel supply to quench their thirst. That includes looking at feed and return line size in addition to pump capacity. A common scenario today is when converting from a carburetor to fuel injection. Carburetors use a low-pressure fuel supply. This is typically in the 6 to 8-psi range. Fuel injection requires a high-pressure fuel supply of 40 to 60-psi and even higher for boosted applications. An electric pump and high-pressure regulator are required for electronic fuel injection (EFI).
