well Yamaha chose 7 valvesBandit1216 wrote: ↑Thu Jan 13, 2022 2:16 pm... Both 4 and 5 valves per cylinder have 68% of the bore area covered, and the only advantage of 5 is relative lower valve weight and equal valve size. Beyond 5 it gets worse....
That was like, 50 years ago? Even the NR is more recent… and more interesting. Yamaha and later Ferrari used 5 valves, but in the end realised that 4 offers the best performance and efficiency (both at prototypes without regulated amount of valves and street use)Tommy Cookers wrote: ↑Thu Jan 13, 2022 2:58 pmwell Yamaha chose 7 valvesBandit1216 wrote: ↑Thu Jan 13, 2022 2:16 pm... Both 4 and 5 valves per cylinder have 68% of the bore area covered, and the only advantage of 5 is relative lower valve weight and equal valve size. Beyond 5 it gets worse....
(for their otherwise conventional GP motorcycle)
+1
This and they were at the limit of combustion speed with that bore size, and it wasn't the fastest engine of that era.IIRC. 20k wasnt seen until the Cosworth V8 of 2006.
I'd like to see that Honda auto ignite system on their old V8...Hoffman900 wrote: ↑Thu Jan 13, 2022 4:34 pm+1
They can't open and close fast enough. Camshafts are REALLLY hard to beat.
5 valve chambers are a mess combustion wise and they struggle with getting good port velocity out of them.
This and they were at the limit of combustion speed with that bore size, and it wasn't the fastest engine of that era.IIRC. 20k wasnt seen until the Cosworth V8 of 2006.
I’d like to see it on a naturally aspirated application as well, assuming it can work that fast.Zynerji wrote: ↑Thu Jan 13, 2022 5:05 pmI'd like to see that Honda auto ignite system on their old V8...Hoffman900 wrote: ↑Thu Jan 13, 2022 4:34 pm+1
They can't open and close fast enough. Camshafts are REALLLY hard to beat.
5 valve chambers are a mess combustion wise and they struggle with getting good port velocity out of them.
This and they were at the limit of combustion speed with that bore size, and it wasn't the fastest engine of that era.IIRC. 20k wasnt seen until the Cosworth V8 of 2006.
Would you quantify that please? One would think that more parts =more weight and friction. I'd love more info on it.saviour stivala wrote: ↑Thu Jan 13, 2022 6:05 pmA V10 and a V12 cylinder engine of the same cubic capacity, The V12 will always be able to be made to rev higher then the V10.