Jesus fuck is this guy retarded???
It is a VERY simple concept!!! Let's work through it together
For example:
1) a car running a T3 turbo, at 1 bar/ atmosphere ( 0 on the boost gauge, neither vac or pressure) @3000 rpm on a cruise throttle, required 5cc of fuel per pot ( example figures!) to maintain an AFR of 14.7:1... If it is running standard yellow injectors, that could be 40% duty cycle, or 50mS.. For exactly the same conditions, but running green 803 injectors, the duty cycle would be lower, say 30% and 40mS due to it being a higher flowing injector... However, the TOTAL amount of fuel injected is STILL 5cc per cycle. You could use a 83lb injector, and be only at 5% duty cycle & 10mS, but it will STILL be injecting EXACTLY 5cc of fuel per cycle to maintain the 14.7 AFR!
2) a T4 turbo has far less back pressure than a T3 turbo, and does not produce useful boost until 1500RPM later (again example figures!) ... It stands to reason, for the same Rpm, say 4000RPM @ 80mph, the T3 will be in its boost region, and have a good deal more back pressure, than the larger, free flowing T4 turbine...this creates more pumping losses, So the T3 will require more fuel at the same RPM to maintain a constant speed!
3) it is BLINDINGLY OBVIOUS that once the T4 comes on boost, it will require MORE fuel than the T3, due to the vast amount of extra air being provided!!
Is it REALLY that hard?
The point James is making is that a larger turbo is more efficient for cruise due to lower pumping losses!! It is not rocket science