I was just wondering why prochargers, and turbochargers can change their internals but a roots blowers still has to have a 123.5 degree rotor twist. I believe this limit has been in place for over 30 years now. I have a new Janis billet blower with all the new tricks but it still has rotors with 123.5 degrees of twist. Why don't the race organization let companies develop new stuff and then limit the overdrive if necessary? Maybe a limit is a good thing so that everyone does not end up making screw blowers but can't we evolve pass the current limit to see what the performance gains would be?