The Ti-VCT engines seem to offer very real advantages in that the variable cam timing can produce more torque at lower RPM. I am not so sure that the direct injection (GDI) offers any great advantage in power output. The Mazda engine used in the Plus 4 SS is a Ti-VCT engine and was rated at 167 bhp in standard form (more than the current GDI Plus 4) and, with the additions of throttle bodies was rated at 205 bhp. Add a set of cams and you would gain a lot more at the top end but probably loose torque at lower revs. Ok if you want to race but not so good on the road.

One of the experts on the forum could probably comment but my feeling is that the variable cam timing is advantageous in producing better power curves but direct injection is more about fuel economy and reducing emissions than about producing more power.

Peter

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