This is erroneous info.........
A roots type blower, which this is, is turning as long as the engine is running.
A. It is belt driven
B. There is a shaft that connects to the rotors
C. There would be no point in a part time blower.
D.. There is no clutch that "turns on" at a certain RPM.
Anybody who watched Mad Max and saw him hit a switch to "turn on " the blower was watching Hollywood
directorial license.

Check this site for pictures of the blower, not unlike the one on the SE/SC Xterras. http://www.theoldone.com/articles/damaged-blower/

The rotors DO NOT turn inwards, they spin away from each other and drag the air around the walls of the housing. Since the tolerances are so very tight, there is
not enough room for air to squeeze around the rotors and into the engine if it were not turning.

As far as the performance issue.....it is the ECU that needs reprogramming. I am not positive but I think that there were some ECU installed into the SC models that were for the normally aspirated engines. The programming did not take into account the added pressures and such.

Another link with a good description of what a blower does: http://www.tpub.com/engine3/en32-5.htm

[ 01-19-2002: Message edited by: lexicon5 ]