Firewall Forward - Custom Exhaust Fabrication

After looking for an off the shelf exhaust system that would fit my requirements and not finding a good match I decided to give Aircraft Exhaust Inc.  a call about their design your own Custom Exhaust System.

The process starts with Aircraft Exhaust Inc. providing a collector based on your requirements and the exhaust port connectors.  You supply the necessary PVC pipe and joints to custom design a system to your exact requirements.  The following show the completed mockup to be sent for fabrication.  

While I was working on the fabrication of the system a couple of other pilots who have planes on the field where I have my hangar stopped by to see what I was doing.  One of them was familiar with the process and started discussing it with me.  The other had absolutely no idea of what I was doing...only that I was building my exhaust out of plastic.  Finally after about 10-15 minutes he couldn't take it any longer and asked "Aren't you afraid that your exhaust will melt?".  I thought his friend was going to laugh himself sick.  We finally explained that this was just a mockup and it would be used to build a stainless steel version.  

A trip to Home Depot resulted in a good supply of 90, 60, 45,
and 22.5 Degree PVC connectors and several 2 foot lengths
of PVC pipe.  Get more than you will need, you can always
take some back.
Start by mounting the collector where you want it to be positioned
when complete.  It must be placed and held firmly in position
while working on the assembly.  The process will take lots of
fitting and refitting.
The above is the completed mockup after gluing all the componets
The length of the individual exhaust pipes are all within 1 inch of
each other.
The number 4 pipe takes several turns that don't appear to be
needed but are there to equalize the length.
I had to assemble, disassemble, and rework several times to
equalize the lengths.  Time consuming and frustrating.
The heat muff for cabin heat will go where shown. If needed, carb heat could be place on the other side.
The underside of the fuselage along the Center will have a
stainless steel panel with fiberfax backing installed.
The fuselage panel will protect the fuselage from any exhaust heat.
The system will also be coated with a ceramic coating.
Care must be taken to ensure clearance between exhaust
components and anything that might damage them.
Or any components which might be damaged by the hot exhaust
The view from the side shows how closely the cowling fits and
how far back the full system will go.
Some adjustments will be needed to the cowling to provide more
space from the exhaust pipes.
The completed mockup is glued together and ready to be
disassembled at the collector for shipment.
When removed from the engine, the mockup retains its shape
exactly as formed.
I was concerned having a large portion of the HOT exhaust
system under the fuselage and what effect that head might
have on the Fiberglass structure.
My solution was to fabricate a protective belly pan from the same
stainless steel material used for the firewall.  I also lined it with
the fiberfax used on the firewall.  The tape just holds it in place.
The installed belly pan is shown in place on the underside of
the fuselage.  It extends back beyond the tail pipe extensioin
and far enough that I could include a short muffler beyond
the 4-into-1 collector.  This should provide complete
protection for the underside of the fuselage.  The pan is
currently being held in place with pop rivits.  I will probably
add some glass and filler to dress up the edges and provide
additional holding power.

Note:  Some of the dates  (2007 and 1/1/2009) are wrong, the camera kept resetting the dates.