Yeah my thoughts too? Could this be part of the friction issue Brown and then Wazari alluded to. I hope he can share his thoughts on this.MrPotatoHead wrote: ↑Fri Jan 12, 2018 3:46 pmGoing back to coil springs over Pneumatic is a very odd thing to do and I find it very very srprising. Even at "only" 13,000 rpm the valvetrain dynamics are very hard to control when using aggressive ramps. Jerk is not your friend.bill shoe wrote: ↑Fri Jan 12, 2018 3:23 pmI read it to mean Honda went from original pneumatic valve return to conventional coil springs to eliminate the pneumatic system weight. It says each coil spring is actually a triple-spring combo, which typically prevents any one spring resonance from dominating and provides light friction damping between springs. Current materials and dynamic modeling make conventional springs possible at revs where pneumatic used to be needed.ncassi22 wrote: ↑Fri Jan 12, 2018 7:22 amThe article mentions the Pneumatic valve system. It dindn't make clear whether the system was reduced in components/simplified to save weight or dumped for a springvalve system. Also it says something about injectors on the exhaust side??? Translation errors or something else?
Would be interesting to know if other engines (Merc., Ferrari, Renault) use coil springs instead of pneumatic, and would be interesting to know if Honda sticks with coil-spring for the higher revs in 2021.
Not to mention the difference in weight between the valve springs themselves and the entire Pneumatic system is not as great as one might think.