[carbonBLUE]

Originally Posted by serialk11r

The reason why I think it's okay to extrapolate is that the engine has cam phasing, but not variable lift/duration. The 2GR-FSE makes power a good 1000 rpm lower than this engine, and in Toyota released papers they indicate an intake cam duration of ~250 degrees or so. For the 1NZ-FXE there are similar diagrams that indicate a ~270 degree intake cam.

The FA20 needs more duration than the 2GR-FSE in order to have good VE at 7000rpm, so it's reasonable to expect slightly longer duration intake cams. If you look at the released dyno charts you'll see that the torque is very weak before 3000. However the specific torque is quite a bit stronger than say the 1NZ-FXE or 2ZR-FXE at low rpm. The reason being, direct injection + premium fuel allow them to use a huge intake cam advance that causes a lot of hot exhaust gas to get trapped in the cylinder. Of course there is a limit to how much you can do this before you run into problems, so the torque under 3000 is weak. If you look at the 2GR-FSE on the other hand, its torque is weak below 2000, but is pretty good after 2000. By comparison, the 2ZR-FXE has torque that increases up to about 4000rpm. So there is definitely an appreciable difference in intake cam duration, and my guess is that the FA behaves somewhat like a direct injected Prius at medium load, low rpm. The cam is probably closer to the Atkinson cycle engines than it is to the 2GR.

In addition, may I note that Toyota's D4-S system created sufficiently homogeneous fuel mixtures at low speed even with a high flow port on the 2GR, so it's possible that an even longer duration intake cam will reduce throttling loss but not affect combustion, improving fuel economy. Direct injection, crazy stuff

Great explination