Sequential Setup?

[Edward Hernandez R]

"For sequential injection, most common method, is to time the injector
 to CLOSE with the closing of the intake valve."

No, the most common method, among OEMS, is to inject while the valve 
is closed. The onion analogy mentioned in a later post is a good one 
once you get fuel into the chamber, but injecting onto a hot inlet 
valve vaporizes a majority(not all) of the fuel before it gets into 
the chamber. Also, some fuel which has piled up on the valve without 
vaporizing gets sheared as it is dragged past the valve and seat,
reducing droplet size significantly. As good as injectors have become,
 they still inject droplets, not vapor. Injecting past an open valve 
will introduce these droplets into the chamber untouched, which, as 
the onion analogy correctly describes, take longer to burn. 
Furthermore, there is risk of washing the oil coating off of the 
chamber walls during open valve injection, which puts engine durability(rings, pistons, bore finish) at risk. 
 
"correct me if I'm wrong. when you go from hi vac to WOT, the only air
 to enter the cylinders is previously measured air between the 
throttle and the MAF and  air passing through the MAF. So the only 
error would be in not measuring that volume between T-body and MAF. 
Unless the distance is large I don't see it  as a problem."

You are correct, except that the volume between the throttle body and 
the MAF is usually large enough to be a problem. Usually, that is. 
Some applications are better then others when it comes to this 
phenomenon.