When launching a stick car, either the tires have to slip or clutch has to slip until the car gains enough ground speed to allow the clutch to lock up without pulling the engine below where it makes power.
Old school thinking was a stick car needed a couple revolutions of tire slip during launch to keep rpm up. You generally had to hit the tires hard enough to break them loose, from there chase air pressure and launch rpm to get just the right amount of tire slip to keep the engine from falling below its torque peak.
Problem is the old school tire slip method doesn't work with radials. With dead hooking radials, the clutch needs to hit softer to prevent pulling the engine down too fast. The softer hit leads to longer lasting tires, less wear/tear on the drivetrain, and less need to chase track conditions.
One way to keep a dead hook from pulling the engine below its torque peak is a centrifugal assist clutch, as these clutches are typically set up to slip against WOT below the engine's torque peak. The higher you launch with centrifugal assist the harder the clutch hits, so the quickest launch with a radial and centrifugal assist clutch is usually all the rpm the combo can handle short of spinning the tires.
Another way to keep a dead hook from pulling the engine down below its torque peak during launch is to use a ClutchTamer. A 'tamer allows you to slow how fast the clutch pulls the engine down against WOT, giving the car more time to gain ground speed before the clutch locks up. That softer hit in-turn allows you to launch higher than you would be able to with a centrifugal assist clutch, allowing you to take advantage of packing more inertia energy into the engine's rotating assy before the clocks start running.
For a street/strip car, a centrifugal assist clutch can be a huge pain in the ***. Settings for the track that allow the clutch to slip below its torque peak are generally too loose to allow using any power during lower rpm casual driving. If you don't want to downshift to pass someone on the highway, you will need to swap back and forth between street and track settings with a centrifugal assist clutch. With a 'tamer controlling the clutch hit instead of centrifugal assist, there is no need to change clutch settings for casual driving.
Grant