so as i lie in bed at 1:30 this morning, tossing and turning trying to sleep.....i came up with this question.

you tune your ecu (in a turbo application) to deliver more fuel during boost...but since if your not under load, you dont make boost....how do they solve that? to my miniscule knowlege of tuning, i would think that they would set the duty cycle for the injectors through the RPM range once without boost, and then with...but that led to another question...ho does the ecu know when to add the extra fuel under boost?does the map sensor tell the ecu...."hey hoe, i smell more atmospheric pressure comein'!!!! give me more fuel!" or how does that work.....

Just a little question i had that has bugged me all day. thanks. (btw: i dont need a super in-depth answer, just a basic one) thanks.
*EDIT* i just read sov's "the real FAQ's about tunning" or what ever and it cleared it up a little with the timing/map/rpm chart....but not completly...from what i can tell the answer is "yes, the map sensor tells the ecu how much fuel to deliver in relation to the MAP reading" but if that were so, then why would you have to tune? so that leads me to belive that i am either close but not quite there with my answer...or im just completley wrong. lol....thanks guys.