The Dyno Chart above is the Magnum Powers Roots supercharger running 20 psi boost as well as a Kenne Bell Twin Screw also running 20 psi boost both on a JDM Stage II engines. Both runs were running VP103 Race Fuel on a Mustang Dyno. The Kenne Bell made 546rwhp SAE while the MP made 523rwhp SAE. The Kenne Bell supercharger made 620rwtq while the MP supercharger made 646rwtq. Note the AVERAGE POWER. The Kenne Bell supercharger made 467rwhp average while the MP supercharger made 459 rwhp average showing the Kenne Bell Twin Screw only made 8 more average hp!!! The MP made the pull with an average boost pressure of 18.3 while the KB was 18.5 average psi. The Mag made 20.5 max at peak near the end of the pull while the KB made 20.3 max near the beginning. The Mustang dyno reads 4% reads lower then typical DynoJet dyno's.

The KB had the small blower pulley and a 9 5/8" lower. The Mag had the Mag 2.75" upper and a 10 3/4" lower. Since the Kenne Bell displacement is larger the input shaft does not need to spin as fast to flow the same amount of air however remember the Kenne Bell Twin Screw male rotor is geared up 50% internally so it is spinning a lot faster internally then the Magnum even with the 10 3/4" lower.