Quote:
Originally Posted by ryridesmotox
Thanks AKI...
I wonder why they don't tune it for the DI injectors to run from Idle to redline and the port injectors to run on a demand level... as demand increases the flow to the port injectors would also increase, increasing the fuel into the cylinders, but the DI stays relatively constant.
Edit: I'm only saying that cuz via the "dyno chart" on that recent brochure post, it seems like it takes a huge hit right in the middle... It doesn't need to do that, it seems that they are switching between the 2 fuel systems rather than using one as a piggyback to the other to increase flow... God I hope that makes some kind of sense, it does in my head at least.
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That's not the real dyno chart I'm fairly sure, the difference in torque is too big for a motor with one lift profile. With one lift profile the torque curve generally has one distinct peak, as below that the flow velocity into the cylinder is crappy and above that there is more restriction. With multiple lift profiles you get multiple "humps", and with continuous duration/lift you would probably get an inclining curve (although it's very programming dependent and such) since the extra intake duration at high rpm just spits air back out at lower rpm, but you most likely can't use the most lift possible at low speed. With a continuously changing lift profile like Ferrari, the "Williams Helical Camshaft" (basically Ferrari except more late intake closure focused, and a moving helical piece instead of one solid piece), or Fiat Multiair (which can change lift a tiny bit more flexibly than Valvematic/VVEL/Valvetronic), you can get just about anything, but in theory you'd be able to get a curve that just keeps going down: frictional losses and lower effective expansion due to relatively slower burning speed increase. However these systems tend to have very high lift built in and aren't as optimized for low rpm, so results vary a lot. They just drew some crap to show everyone how D4-S improves everything.