[Dimman]

Originally Posted by serialk11r

AVLS still has intermediate rockers though, which the diagrams and dimensions suggest don't exist...My current explanation is going to be that they detuned the engine like crazy to get it to super duper ultra mega low partial zero emissions VI (or whatever)

About Valvematic, I don't think it would just "bridge" the 2 "humps". The thing with Valvematic is it would come with a super aggressive profile cam optimized for peak rpm operation, and then it cuts down on the lift and subsequently duration to get it to work at lower rpm. Inevitably what happens is that you cannot really use the extra duration at most rpm ranges, but you have to cut a lot of lift too, so the lift is not really optimal most of the time at full throttle (too high). They could cut it down more, but then duration gets cut, and you have less air to burn. In that situation they'd probably have it programmed to have duration cut more since it would improve thermal efficiency and combustion efficiency a little bit, but it's hard to say how the torque would behave. Since at 3000rpm ish losses tend to be the lowest, a 3d continuously variable duration cam plus continuously variable lift (aka the perfect cam system) would be able to get a torque curve that falls very slowly and gently from 2-3k rpm all the way to redline, but when you control lift and duration together you cannot optimize low rpm power that way. Nissan VQ37VHR seems to have freakishly consistent torque from 3000 all the way to 7000, which supports this theory I think. The max lift profile is designed to work best at 7000 rpm or maybe a little less and then they "throttle" it away for lower speeds.

No AVLS? Argh... I was working under that assumption for my previous prediction, but I only remembered that it looked like the FB20 didn't use it, and that the cam carrier was modular, so the FA could have used it. It was also the best I could come up with for the high torque peak.

As for the duration changes on Valvematic, that works with the peak to peak line idea as well. The VVTL-i is not simply a lift change, it switches to an entirely different profile. The lift AND duration are different between the two stages.