Kinda drips from the tongue doesn't it?
Fundamentally Different Compression Topology
I think I better get me some of that for my car. Sounds fast.
xtn
FDCT? Rad!:evil:rotfl
Actually, the lysholm/Whipple is a screw-type with an internal compression i.e. the air is compressed between the screws and the threads of the screw get tighter as you move from inlet to outlet. The tolerances are much tighter than those on a traditional roots so they can support a higher pressure-ratio(boost) vs. a traditional roots.
The TVS is based on roots but has the twist of a screw, 160 degrees, additional lobes, and constant screw-pitch. The tolerances are also very tight, which adds to the efficiency. I believe this was done to avoid patent infingement with Lysholm.
Looking at the compressor maps for both, the TVS looks to have similar overall efficiency, BUT larger highest efficiency island. They look to be largely the same from a performance standpoint.
In the interest of full disclosure, my XP car has a Lysholm/Whipple. My street car, hopefully will soon have a TVS.