As everyone in this forum knows, Renault introduced the turbocharged engine to Formula 1 in the late seventies, with a 1500cc version of their Le Mans-winning 2-litre V6, soon showing that the turbo was the way to go. Apart from BMW, Hart and Alfa Romeo, most of the competition followed suit with their own turbo V6s, and very successful many of them were. BMW and Hart had sound, but different, reasons for using turbo L4s; only Alfa Romeo built a turbo V8, this last without success.
Concurrently, the Cosworth DFX Indianapolis turbo V8 was developed, based on the legendary DFV, and was just as successful as its parent. In fact, the Indianapolis brigade had a ten-year start with successful turbo engines, both the Offenhauser L4 and the “four-cam” Ford V8 dating back to the late sixties.
So it is interesting that Ferrari, Honda, TAG and Ford (Cosworth) all opted to build their F1 engines as V6s, following Renault’s lead. (Even though Renault’s original choice of the V6 for their competition engine in the early seventies does not seem to have been with turbocharging in mind).
And, also interestingly, since 2014, the FIA has mandated turbocharged 1600cc V6 engines for F1.
This raises the question: Is the V6 particularly suitable for turbocharging when the total displacement is 1500 to 1600cc?
Or has it been chosen simply because Renault happened to turbocharge an existing V6 engine, whose performance they needed to enhance, so as to win at Le Mans? And met with resounding success. (The straight-6 may reasonably be dismissed, as it is none too suitable, architecturally speaking, for a modern racing car, and for the majority of modern road cars too).
Those Indy turbo L4s and V8s were initially 2800cc, later somewhat reduced if I remember rightly. Could the difference in displacement account for the difference in approach? (Seems unlikely, as here, too, existing “aspirated” engines were adapted and developed with turbochargers).