On 12/05/2020 17:16, The Natural Philosopher wrote:
None of this relates to fuel efficiency: That's is far greater these
days because of electronic injection and mapping allowing an optimal
fuel level and inlet pressure depending on the load and RPM. That and
lower friction materials nets you a more efficient motor overall.

That fits my understanding.

So why have such complicated engines when these above things can be
implemented on a simple OHV engine doing less than 5krpm and no variable
valve timing?