Frederic Breitwieser/turbo discussion, design Q's

[ECMnut at aol.com]

HI Gary,
 Is a 4-into-2-into-1 turbo header superior  to say,
 4 tubes converging right at the turbine inlet?
I'm trying to establish some rules as to when one design works
better than another (while lag is a fairly big concern).   Is there a 
rule of thumb, say with 4 vs 6 vs 8 cylinders?   Mine is a 4cyl.
The info on the Porche design is very  interesting, but 
does anyone know why they chose that design over others? 
With the 4-2-1 setup, does the firing order dictate which tubes 
get paired together?  For example, should the first merge join 
two cylinders that are farthest away from each other in the firing 
order?  
Thx
Mike

>  think a good basic 4 into 2 into 1 header is the way to go.
>  Anti-reversion tricks may help, I don't know.  Look at a Porsche 944 Turbo
>  setup.  It has practically a full sized header.  The turbo is on the intake
>  side.  Typical lengths are 18 inches to the first merge, 1-4 and 2-3, then
>  24 or more inches to the second merge, right at the turbo.  A dual scroll
>  exhaust housing separates the pulses even further.
>  
>  Gary Derian <gderian at oh.verio.com>

>  >Does anyone know of a good example of reversion tubes, somewhere
>  >on the net?  I'm gathering materials to build a 2.0 Ltr 4cyl turbo
>  >header.  Also, if there are some good rules for volume ,
>  >primary tube size/length that you are aware of, please
>  >lemme know.  The engine is a 16v SOHC Neon unit.
>  >I have a spare of this particular engine, so I'll push it
>  >pretty hard.hard.