http://www.muran.am/sunny/sunny_performance.htmJust a lil extra info.
I found out more info on the Series 2 QGs (CVTC- E-THROTTLE).
CVTC advanced and retard timing depending on driving conditions. VTC only ADVANCE to improve torque at low to mid range.
EDIT: CVTC plunger (valve) can shift direction of oil, hence, it can retard timing or advance it, and it seems VTC plunger cannot, only in one direction (advance)....There are no detailed information on VTC in service manual, but CVTC is nicely explained...
CVTC retards timing at high speeds to increase power from mid range to high end.
CVTC equipped QGs has an alumium valve cover vs the VTC black plastic top.
CVTC also came without EGR (exhaust gas recirculation)
The series 1 has a different lower intake plenum, with this thing nissan calls a "swirl control valve" that stays partially closed at low RPM to increase torque, and dissengages at WOT. It was disconinued for the series 2.
QG's are lean burn ENGINES...it uses a bit of extra air to improve performance at early rpm
The solenoid valve controls swirl control valve’s shut/open condition. This solenoid valve is operated by the ECM.