Quote:
Originally Posted by Travis Q
You've ALWAYS got to take boost into account. That and intake valve area. Bigger intake valves require more spring pressure, since the boost acting on the valve has more surface area to act upon, and therefore "takes away" a larger amount of seat pressure. Also, stainless valves will need more spring pressure than a titanium valve will because of the mass of the valve itself. Of course, rpm range comes into play, too. More rpm requires more spring pressure.
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ditto
Quote:
Originally Posted by Travis Q
For a stainless valve with a diameter of around 2.20 inches(2.30) in a turbocharged application seeing 20 psi boost pressure @ 7500 rpm, I would want absolutely no less than 325 lbs on the seat. Titanium valves buy you the ability to run less pressure (at that boost level), but don't mix well with extended street driving. More boost will require more spring.
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ditto
Tony vacuum fit all valves with specials seats. There are a few ways to gain RPM like a head design w/relatively short valves/pushrods with 11/32 stems.(lighter valve/better seal/proper seat angles = less valve bounce = less seat pressure.)
Quote:
Originally Posted by Travis Q
As Tom alluded to, there is no free lunch. In one area or another, we must all pay the piper. There is always compromise when putting together a high powered engine, especially one that's going to be run on the street. The question is can we tolerate negative aspects of that compromise. Turbocharged engines allow us to have enormous power levels in street driven applications with less negative compromises.
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ditto!
Dyno will tell our
street RAV we were so surprized making power to 6700RPM!!! Our RAV design parameters paid off! With race springs we project over 800HP@7600.(Remember no high dollar tricks like Ed's engine)
Quote:
Originally Posted by Travis Q
Still, there is no free lunch.
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Yes..so when we hear that the engine is to be occaisionally street driven we decide how to fit the application.