Good work Greg..

[Greg Hermann]

>  The header design you spoke of is a very good design.

Thanks! Just so as we all understand that there is no "IDEAL" header design!

 These headers teamed up with a merge in the
>tertiary pipes works very well. The merge was accomplished by cutting
>off the outside 1/2 off of two 3 inch 90's and welding them together in an
>x or )( fashion. At about 6000 RPM this setup would develop a beautiful
>Indy car like whine through 7500 RPM. Check out the next NASCAR
>restrictor plate race. Look carefully at the exhaust system as they fly
>through the air and you will see what I am talking about.

No need to look under those circumstances--there's a much easier way to
view it--look at a picture of it in the Burns Stainless catalogue!! :-)
<www.burnsstainless.com>
>
>Greg can you please elaborate more on that resonance/expansion
>chamber you were talking about? Thanks!

Picture a straight piece of pipe, appropriate size. Support it so that
neither piece will move when you are done with the bandsaw or tube cutter.
Make the first cut (square to the pipe) so that the length of the tertiary
tube to the cut from the merge of the secondary tubes to the cut is the
same length as the primary and secondary tubes. Make your second cut about
1/2' or 3/4" behind the first cut (don't need much length to the gap you
are creating.) (Remove the short piece!) :-)
Now build the plenum chamber around the gap so that the total volume of the
chamber is about twice the volume of the tertiary tube up to the first cut.
(more volume does not hurt, but about twice is about enough to do the job.)
Shape of chamber (oval, round, etc does not much matter, enough internal
volume is what does matter.) The chamber is concentric with the pipe, and
usually most of it is positioned ahead of the gap, sorrounding the tertiary
tube. From the gap back, it does not much matter what you do as to length,
so long as the tail pipe (and straight thru muffler or mufflers, if needed)
stay the same diameter as the tertiary pipe. The header will see the gap in
the pipe as an open end for pulse tuning. I SUSPECT that such a plenum may
even work better than an open pipe terminated at the same length as where
the first cut is.

I  think that the "cross" between the tertiary pipes on a system like you
described is a "lazy" way to get closer to the tuning of true, crossed over
180 degree headers on a V-8. If you are willing (and if it is possible, no
small if there!) to do true 180's, I do not think that the cross would do
much for you at all.

Regards, Greg