If i am right it keeps your turbo spinning inbetween gear changesand on launches so there is like it says no lagg from the turbo. ussally used on race/ rally cars where turbos are only used for a short time then changed. aparently it eats through ure turbo and it wont last very long with it.
I have had some thing smuliar done when had my stage 2 at jabba, at high revs when u dip the clutch for a gear change the engine jumps 500 revs before entering the next gear there for keeping the turbo spinning i asume = less lagg.
some one else mite have a better opion though.