Just doing some thinking from an engineering point of view:
The move towards lower displacement (and lower cylinder count) with forced induction is aimed at conserving fuel usage but providing similar power.
The general idea being:
· There isn't a constant need to operate at 100% throttle and at 100% power
· Higher mechanical efficiency from lower loss -- namely in reduced frictional loss (e.g. moving 4 pistons vs. 8 pistons)
However, there are some interesting concepts that should be taken into consideration:
· All SI engines are subject to pumping loss, namely, the throttle (excluding GDI systems)
· As [cylinder] displacement grows, consumption will fundamentally be less, due to a boost in thermal efficiency (surface area : volume ratio)
Can we have our cake, and eat it too?
Our cake (fuel consumption) favors a reasonably sized >n cylinder engine operating with a large throttle opening and relatively low rpm (2500-3500rpm). Without comparing powertrain [e.g. transmission & gearing] and road loss [e.g. areo], this is possible with your Sti, Evo, GSX, etc…
But what compromise do we need to make to eat our cake?
Power (digestion of our beloved cake) is a function of many things, but namely cylinder pressure. If one can fill the cylinder with air (oxidizer), provide a fuel (octane), and ignite the mixture at the optimum time without abnormality, one has eateded their cake.
Common sense dictates an engine that displaces 2L with 4 cylinders has to at least triple the cylinder pressure as 6L 8 cylinder, thus, there will be a considerable amount of additional force on components in >n cylinder/displacement engine. For argumentative purposes – there is an invisible line of limitation to engine size and output – the size of an engine is still a major factor in power output.
We might not be able to fully engulf our cake, but with the help of technology, we can devour a few forks worth….