|
So variable valve lift just means the cam lobe profile is essentially switchable, not just phasing where they change when it opens and when it closes but still using the same cam lobe, just changing its rotational position relative to the crankshaft. The most advanced variable lift systems control lift and duration together, allowing a huge decrease in pumping loss and thus a huge increase in fuel economy. On the performance side, what they allow is greater power because the lift and duration can be rpm optimized.
I am fairly sure any variable lift system uses some sort of intermediate rocker to create that effect, and this usually adds some height (Valvematic ZR engine for example, is 34mm taller over the regular dual VVTi ZR without lift control IIRC) over the intake valves. But this engine looks to be the same size as the previous one, so the only extra space you get to stick something like this in there is however much they trimmed off the stroke length, which is probably not very much.
|