For a turbo cross-plane V8 with short log-style exhaust manifolds, I think the exhaust gas pressures are a big deal. See the attached graph from Vannik's software. At IVC, the pressures help close the intake valve. At EVC, there's a nasty pulse interference in this cylinder at 5500 rpm right at EVC that fights against the valve closing:MadBill wrote: ↑Thu Oct 31, 2019 7:25 pm I haven't seen any definitive data showing that exhausts do bounce higher or sooner than intakes. Since bounce can only occur after EVC and by then (40°+ ATDC) the piston will be out of reach of any still-connected ex. valve, gross signs of P-V contact can only be the result of float.
Float and bounce by the intakes leave more subtle clues and less immediate destruction, so judging only by the damage, it would be easy to conclude that exhausts are the weakest link due to sooner/higher bounce.
Also, typically, exhaust valves are lighter than same-technology intakes, plus commonly have less lift and more duration, both of which make the exhaust spring 's job easier than the intake's
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Normally aspirated and with headers, story might be completely different.