Turbo header design

[Clarence Wood]

WOW!  Thank you Greg!  
  Now, how do you accomplish the task of giving the exhaust gasses somewhere to go freely during the "blowdown" part of the exhaust stroke?  What is the best header design to accomplish this for turbo charged engines?  For NA engines?  Is there one technique that seems to be more effective than other techniques?  Is it pipe width, or length or both?
  Also, what is "sonic energy"?  I know it refers to sound but I have never thought of sound as being part of exhaust energy.  How does sonic energy create a scavenging pulse?  Is it something you have to design into the header?  If so, what is the criteria for the design?  I guess what I am trying to ask, is, how do you look for this in a specific header design?  What tells you that the header design uses sonic energy effectively?  How does the tri-wyes header relate to the above?  

At 01:21 PM 1/7/99 -0700, you wrote:
<snip>
>All my experience says that the biggest gain from headers is from giving as
>much of the exhaust gas as possible somewhere to go freely during the
>"blowdown" part of the exhaust stroke--before the piston starts back up
>significantly. Yes, it's nice to have a low pressure pulse in the exhaust
>port at overlap, and that pulse helps to scavenge clearance gasses if you
>have it there at the right time, but the longer you can keep the blowdown
>stage flow sonic, the less work the engine will have to waste pumping
>exhaust gas out of its cylinders, and the more sonic energy there will be
>available for creation of a scavenging pulse!
>
>Regards, Greg
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