Quoting Jim Akiba <syncrolist@BOSTIG.COM>:

> Either that, or he's ahead of the curve... clutch driven blowers have
> been
> popping up in articles recently.
>
> Jim Akiba
> From: Sudhir Desai [mailto:sudhir.desai@GMAIL.COM]
>
> Maybe he's talking about superchargers with a bypass valve that is not
> vacuum operated?
>
> Sudhir

Um, I'd forgotten about clutched blowers... they have existed for years
(see the XD or XC Ford Falcon coupe in that Aussie film Mad Max 2"). Of
course these are either on or off, nothing in-between. Sudhir's idea is
possible, with either a motor-or-cable-driven valve.