I have qn OG red that just got rebuilt has no anti surge

How much power does the antisurge add?

 

Its' purpose is to help reduce surge and has nothing to do with increasing power. Surge occurs when the turbo is putting out more air vs what the engine can ingest so the air backs up on the compressor wheel and causes surge, which is typically audible and can cause the car to buck.

 

Yeah im only on pump gas 24 psi so not really needed then I guess

 

The FAP cover does increase flow, but its more so when the compressor is approaching or at the choke line. You won't notice at low boost.

The surge 240Z is talking about generally occurs during spool up, especially in higher gears. So the FAP cover may help a bit there.

 

Do you currently have an issue with compressor surge? If no, then don't worry about the cover, but also understand that having a surge cover does not guarantee you will eliminate surge.