Robert N. Eaton spoke forth with the blessed manuscript:
> At any rate, two valves of half the valve surface area weigh about half
> of what one valve would weigh and would need lighter valve springs. Less
> reciprocating weight equals higher rpm without valve float, and that
> equals more power from a given displacement engine.
Two small valves weigh more than one single one. A lot of the valve weight
comes from the stem, not the face. More power, less torque. Torque actually
moves things, HP is just a way to espress torque with reference to RPM.
> Probably the most elegant answer to this problem was the one devised by
> Ferrari a couple of years ago, when they set for themselves the task of
> wringing 900 horsepower from a
> V-10 twin cam multi-valved unblown three liter engine. They figured that
> if they could get 300 hp out of a three liter engine at 6000 rpm then
> they would have to spool up the engine to 18 grand to get 900 hp. No
> known valve spring would survive that, so they used 150 lbs of air
> pressure to close the valves. Air has no natural frequency, so the
> valves could operate at this rate. The only thing limiting the rpm was
> the reciprocating weight of the pistons and connecting rods. These they
> had to fabricate from titanium, at a cost that probably made even
> Ferrari blink. I never found out whether they ever raced that engine,
> but what a marvelous tour de force!
Titanium is denser than Aluminum. Thats why we use aluminum for pistons. Ti
is fine in the conrods, but doesn't make sense for the pistons.
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