X-Mozilla-Keys:                                                                                 
Ed Anderson wrote:

Chuck Dunlap wrote:

Here are two pictures of my manifold assembly. It uses 1 1/4" .050 wall
primary tubes and 1 1/2" .065 wall secondary 6061 tubes from Burns
Stainless. They are welded to a 1/8" thick (!) flange on each end. I
would use 3/16 if I were to do it again, but I thought the 1/8 would be
easier to weld.  I used the 1 1/4 and 1 1/2 size because that is the
size of the openings in the stock 90 degree manifold piece. The dynamic
chamber is built to the shape of the cowl and has nylon horns on the
inside that I turned on the lathe. The throttle body is from a 280ZX.
The tubes were welded locally. The tubing assembly weighs about 2 1/2
lbs.

Chuck Dunlap

Great looking manifold Chuck. If you don't mind I would like to put it
on the web site as a good example. Credit to you of course.

Paul Lamar

 Chuck, approx how long are each of your tubes from flange to entry to
dynamic chamber.  From my calculations, the longer the tubes the lower the
rpm the dynamic pulsating effect will have a supercharging effect.  Of
course it also depends on the effective length of the dynamic chamber path
as well.  My calcuations indicates the stock manifold produces a
supercharging effect (large tubes and smaller tubes different path length)
between 5300 and 6300 rpm with the larger tubes having the longer path and
effective at lower rpm and vice versa for the smaller tubes.  I assumed
speed of sound at standard sea level for pulse propagation speed and given
that the intake manifold is less than sea level pressure and the pulse would
therefore travel slower the rpm range effect could be lower.

Neat work!

Ed Anderson

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