J.A.W. wrote: ↑
Sun Jan 30, 2022 3:33 am
gruntguru wrote: ↑
Sun Jan 30, 2022 12:34 am
And the bigger valves need more lift to reach their potential flow.
Or use all the poppets as exhaust valves, as in a Detroit Diesel 2-stroke
lots of tiny valves wouldn't need more lift
poppets & ports is limited by the brevity of the 2 stroke exhaust period
extreme bore:stroke ratio allowing more rpm is helped by .....
Al/Be MMC (banned) and NR 500 or novel architecture (banned)
(relatively) friction reduces as stroke and displacement are downsized - and bearing losses aren't increased
extreme bore:stroke ratio is hindered by.....
(relatively) more heat taken to coolant via 'piston area' than saved by displacement downsizing
so it's heat loss vs package benefits of downsizing