Hi Paul-

  Here are some photos of what I put together to add a heat shield to
  the VAM muffler.  The tabs are a 3/4" standoff, and cover roughly
  240-degrees of the VAM -- about as much as practically possible.  The
  heat shield is .018 SS.  Not much to it really, although getting it
  installed was a bit of a challenge given the engine mount tubes.  I
  think it is going to do a great job for us.  A bit overkill on the
  pictures -- feel free to "edit ruthlessly" to a more appropriate set.

  Ran the engine after getting everything installed; with the blast tube
  hooked up to the cabin air vents, got lots of toasty warm air just in
  the the few minutes of taxiing around.  I suspect routing all the
  blast tube air into the cabin will be just too much heat, so we'll
  have to think of a way to fabricate some sort of waste gate so we
  don't cook.

  Mark  (Rocky Mtn High)

  Thanks Mark. Good pictures.

  Paul Lamar


  Hi Mark,
  Given the propensity for the rotary engine to melt away
  interior muffler parts, please install
  a carbon monoxide monitor in your cabin. We don't
  want you to die! Would look bad for the rotary ; )
  Dave M


How is the interior of your VAM Muffler constructed, can you provide a cut
away drawing?

James Ealey

Muffler's work by rubbing the exhaust gases on surfaces losing energy
through friction. Also pressure is lost in the exhaust system by some heat
being dissipated. Sound is pressure waves.

The VAM works by adding surface area for the gases to rub on.
The central tube provides that extra surface area. In theory the gases swirl
around inside the tangential muffler before exiting.
However the surface area must be cooled so a blast tube is connected to the
central tube. This basic design dates back to VW's in the 1930's.

The 321 SS center tube must be at least .065" wall and 321 SS .090" wall for
extra safety. If this design does not meet your needs on its own it would be
possible of course to install a second low cost automotive muffler under the
engine as the exhaust gases will have cooled off by that time and lost some
energy.

Paul Lamar



Paul, I have 2 questions.
Do you know where to get .090 wall 321 ss tubing? I have tried to find it at
burns, and online metals, a couple others.

Would a tight bundle of 3/4 .065 wall 321 tubes welded together make a
reasonable blast tube? it would increase cooled surface area and add a
little to the Od surface area as well.
C. Smith

http://www.twmetals.com/
http://www.sanborntube.com/htmdocs/index.html

This is a good one. See the attached pdf.
http://www.rjsales.com/products/tube/gauges.html
They have .065, .083 and .125. If in doubt use the .125.


Well I am not sure you would get enough air through them
to prevent melting. We have tested the 2 inch .065.
You could go up on the wall a bit and try it.

Paul Lamar