What uses a fuel dampener and what for?

[BR3W CITY]

AFAIK it was mainly the early Fbody and Ybody cars that had FPD's. Its the extra "thingy" when looking at Fbody vs normal returnless fuel systems. It is not "needed" and if your running a good pump and factory FPR, the ECM fueling should handle any change created by the injectors draining down the rail.

Its usually something you'll see on higher-performance factory variants of cars, where the needed injector duty cycle causes draindown on the rail ahead of what the pump is supplying @ rail pressure. IMO its a factory bandaid.