DiogoBrand wrote: ↑
Wed Feb 28, 2018 3:55 am
So from what I know, F1 N.A. engines have for a long time been engines with short strokes, big bores, relatively low torque and RPM as high as possible.
So I know that for the same amount of torque, higher RPM equals higher power, and I guess shorter strokes work better at higher RPM, but apart from that I'd like to know why they did things like they did:
Pretty much no other racing series that I know of have engines like that, so why did they do things like that in F1?
What would be the downsides of an engine with longer strokes and narrower bores? Couldn't they achieve the same power with more torque and lower revs? (All of that with N.A. engines).
Torque and power are connected. Basically, power is torque x revolutions/time. So if you want to have more power, you need more torque or more rpm. In NA engines, this is done with more rpm (if the capacity is restricted) or with a greater capacity (the cheap options). That high revving engines have a big bore and a very short stroke has to do with the piston speed. The max piston speed (at the moment) is around 10.000 ft/s. So, if you want more revs you need to make travel of the piston as small as possible.
As time and engineering possibilities develop, F1 was going into extremes (as always) and they mandated a minimal bore to keep the stroke a bit normal (and affordable). A while back I saw some KTM pistons that looks more like plates then pistons... really amazing what they can do these days. As a final restriction they limited the amount of revs, basically levelling all engines to the same power.
With turbocharged engines this all is very different. Revs are not important because they are not the source of the amount of air going trough the engine. More air is more power because you can put in more fuel. It's all about boost pressure. Of course, in the case of efficiency there are sweet spots with capacity and revs, but in theory they don't matter. Its about how much fuel (energy) you can burn.