I have started on my sidepipes and thought I would post a couple of pics.
I have used a 3" collector with a 4"-3" reducer that has been cut down, same with the outlet end but have used a 3" bend for the tip.
Both the front and back assemblys have a sleeve welded in from the inside to locate the outer 4" section of the pipes, these will be attached with socket head cap screws around each join.
I have located 4" cats which will sit in the 4" pipe and the remaining will be a home made hotdog muffler.
Expanded metal mesh rolled into a 3" pipe will go up the centre and as you can see in the pics on my gallery ceramic fibre wool will be wrapped around it.
The wool is used for boiler refractories and the like and is great stuff its not even itchy if you get it on your skin. You can hold an oxy torch to one side and your hand to the other, so hopfully the outer of my pipes will not get too hot.
The wool is not that dear either, enough for a set of pipes would only be worth about $20. I buy it by the roll so if anyone wants some give me a ring on 0407 110641.
I had thought about sandwiching it between a sheet of ally or stainless over my pedal boxs to keep out the heat
Gav