Not getting fast in short time

[CasTex]

Hi there. My GTX 260 seems like doesnt get fast in short time. I hear the brang brang brang engine sound first and then it gets fast, is it normal ?
The top speed I see aroudn 62 mph in wavy water so it shuld be ok, but why it doesnt get fast in short time ? (sport mode)

 

[POPPS]

Brang brang?..check the super charger.

 

[CasTex]

But if its about spercharger, shouldnt it do low top speed ?
"Brang brang" its not an annoying sound, just sounds like that, is it normal ?

 

[CasTex]

Ok I found it, it sounds pretty similar on this when he U turn his jetski,

but on me just at when I suddenly hit gas 100% suddenly on straight

 

[ski-d00]

It's called cavitation and you need to change your wear ring/impeller.

 

[CasTex]

Alright, I found the reason. Do you think that these can be repaired or need to be replaced with new ones ?