Variable cam timing uses a secondary pulley assembly on the exhuast cam pulley(contour engine) to control the timing of the valve opening and duration in order to minimize emmissions, hence the contour zetecs with VCT don't have EGR. The regular ZX3 engines in the focus use an EGR system and don't have VCT. The SVT Focus uses an EGR system and only has VCT on the intake cam. Anything else you wanna know?
