sorry, it says atmosphere because that diagram is from a series 3 GSL-SE naturally aspirated engine (notice the top feed injectors). Boost pressure (and atmospheric depending on engine load) is fine. That's how the 2nd gen turbos did it--the
atomization ports were fed by a port on the UIM that pulled air from before the throttle plates. in fact, the series 5 had 3 atomization ports, one for ...