its honda's own information, the link is in my previous post, and you are right, having the vtec at exhaust cam doesnt make sence on a turbo engine of this class. although one of their own information portals also say that one design was with the vtec but doesnt say in which production models,
you maybe right, but as far as I know its 1v/2v with a 2 rocker arm setup, the D series had a 3 rocker arm setup and thats why people sometimes confuse it.
maybe the VTEC-E thing is the one confusing people, i-vtec had this incorporated in it to some extent.
anyways, i maybe wrong, can you share the source/ link which has the actual working? I had a detailed discussion about it in one of the vtec forums and it was waaay back in 2010, and this is what he emailed me. These discussions were on vtec.net/forums.
"the original D15B VTEC-E engine runs 12valve to enable lean-burn (or what some likes to call 'stratified charge') mode in order to run at very lean air-fuel ratios. But it is equally possible to implement a 12v/16v wild-cam VTEC system, i.e. either 1 or both intake valves are working off a very wild, racey cam timing.
Indeed, a 12v/16v system is capable of almost doubling the size of the intake valve once VTEC 'opens' the secondary valve. Of course there is a physical limit to the absolute size of both valves (dictated by the bore of the cylinder) so the 12v/16v system is restricted by this limit in terms of increasing the effective valve size. But on the other hand, the 16v 3-rocker system has a lower limit in effective valve size eventhough it can adjust valve timing because both valves are always operating so it cannot deliver a very small valve size without impacting air-flow at high rpms. So ultimately a 12v/16v VTEC system will not be able to deliver the same power as a 16v 3-rocker VTEC system but it can be quite respectable too. Conversely, the 16v 3-rocker system will not be able to get anywhere near the fuel economy as the 12v/16v system but again it can be quite miserly in fuel consumption too. Honda did offer us the best of both worlds of course and that is in their incredible 3-stage VTEC D15B engine, an engine which has a VTEC system to offers 3-modes, a 12v, 16v and then 16v with higher valve lift and longer valve opening. It was indeed a technological showcase in its time. In the current generation of L and K series engines, that engine is effectively replaced by this L15A VTEC we are looking at now as well as the 12v/16v K-series engines.
So the L15A VTEC uses a 12valve/16valve VTEC system. A nice by-product of a 12v/16v system is the offset placement of the intake valve during 12v mode and this gives us a nice property of inducing swirl in the intake air-flow besides enabling two effective valve sizes. At low-rpms, only 1 intake valve opens while the other is basically 'dead' or not operating. By using this with optimally designed intake ports and piston heads, a swirl is induced in the incoming air-fuel mixture and this helps to enhance the efficiency of the combustion just like in the i-DSI versions. It is not possible to achieve the same level of efficiency as with the i-DSI system of course, but it is good enough to enable the L15A VTEC to achieve almost the same levels of fuel economy as the older D-series engines, the VTEC-E and the 3-stage VTEC D15Bs."
