Wow , now we have problem, even with readig . I 'll say it one more time : " If you look in to engine diagram, you will se that Torque line is horizontal between 2500 rpm and 3700 rpm "

 

You are absolutely right and down to the point. It is up to us how we will utilize potential out-put of our engines.
All the relevant data ( I start to like this expresion ) are allready in a very complex mathematical algoritam in the ECU. The only thing that we have at our disposal are RPM's as far as engine is in the question.
There for, one look at the engine diagram explane everything - to those who understand thing or two about engines . All that I said so far on this subject, can easily be put on test in real life. Simply try you car in that RPM range of 2500 - 3700 .

 

The torque range is flat throughout 2500-6000 rpm with torque varying between 82-89 lb-ft at the edit: wheels (i thought those were numbers at the hub but they're not)
(Temple of VTEC Rumors and News - TOV Dyno Test: 2007 Honda Fit Sport 5MT.

The torque figure gives very little useful information for fuel efficiency because it doesnt give us anything meaningful. Torque must be multiplied through a gear ratio to determine torque at the wheels but power is constant irregardless of the ratio in use. A certain amount of power is required to maintain any given speed, thereby making the power figure the one we need to look at.

Don't pretend to be someone who understands anything about an engine when you cant grasp the basics of the relationship between torque and power.

Power and fuel consumption are in direct correlation to one another, when you make 100ft-lb of torque at 1000 rpm you're using less fuel than making 100ft-lb of torque at 2000rpm.

Please, if you're not going to post constructive ... scratch that ... if you're not going to post something which obeys the laws of physics, please refrain from posting at all.

 

This statement provides no useful information.

This also provides no useful information, and to clear things up the ECU takes different inputs to determine how much fuel to inject, under most circumstances this is goign to be stoichiometric. The ECU also determines the ignition timing but does very little else which is relevant to the discussion at hand.


This again provides no useful information.

All that you've said in this subject so far has been wrong, be it your theories or your data.