From Whipple Industries (the supercharger company): Most fuel injection manufacturers under-estimate the importance of correct application of a dynamic pressure damper in the fuel system. A damper is critical to the proper function of any EFI setup. Rapid cycling of the fuel injectors and fuel system components in a running engine combine with the non-compressibility of the fuel; and create high frequency pressure waves in the rail. These pressure waves can cause substantial variation in the fuel delivered by the injectors; causing numerous running problems that are difficult to trace, in addition to increasing stress on the fuel pressure regulator.