by eco engine with timing control on exhaust, i meant yaris and by "similar displacement performance engine" I meant L15 without valve timing control on exhaust.
Maybe i know less about engines, but you certainly need some reading classes, I never said that there is exhaust valve control on L15.
The major re-work in the "updated" L15z1 was the composite intake, the biggest purpose of which is "lightness" aka less weight. The downside of which was that some after market camshafts for L15A(s) were deemed incompatible..
SO when you say being lighter is irrelevant it assures me that I know more about engines than atleast you.
also what changed with the intake manifold in the "newer sohc L15z"? can you share your wisdom? dnt give me the composite intake rebuttal as you dont believe its relevant.