[max_torque]

I have been trying to understand the main differences in running with direct in-port (ie injecting in intake runner of each port) and post intercooler injection in conjunction with a vehicles std EMS.

I have made 1 major assumption, that at the point of ignition all the water has been vapourised due to the high temp and pressure in-cylinder for both injection positions(is this valid??)

If the air mass flow, AFR, and WFR, turbo / IC efficiency & effectiveness are the same for each method, then the charge temperature at the point of ignition will be similar? (need to further understand the heat transfer to combustion charge along the length of the intake system / chamber, ie does in port injection actually cool the head metal temps etc?)

However, for the post IC injection, the engines' management system will be able to "detect" the presence of water via the reduction in plenum air intake temperature, so adding fuel and advancing ignition timing. This will take advantage of the cooler charge, and combined with a higher manifold Vol eff due to the denser plenum charge produce more torque.

With direct to port injection, the EMS cannot sense this, so there is unlikely to be any power gain on a std EMS system, unless fitted with 2 things.
1) active and aggressive knock control (ie can advance spark agressively till knock is sensed (typically this is now adaptive (ie Bosch ME*.* etc), and may take some time to learn the new knock threshold)
2) EGT sensing, Again some applications of Bosch / siemens ems run with pre turbine EGT sensors to control component protection overfuelling.

Does this explain why people typically see a greater benifit from post IC water injection on road cars without specifically mapped EMS?