999 999 Termi Replica - Exhaust Coring Revisited

Thought I would have a crack at coring the 999 standard exhaust silencer today.

Been looked at numerous times by various people before I know.... but I am trying to make a direct replacement for the Termi Slip on so you can use the DP Carbon Cover too.

I am also trying to make the method repeatable so I can make a few of them.

Hopefully it should come out looking half decent and not a Scrapheap Challenge version. I am basing the internals on the Termi Slip on so it should sound similar too.

 

I decided to cut the top off so that the inlets and outlets and on the same piece of silencer shell.
So I started with a cut across the inlet end and another in a vee shape at the outlet.

 

Next was to cut through the seam welds and also a slot on each side through the internal strap (for the Top Mounting) - This is where you can see the weld beads from outside. Just used a 4 1/2" Grinder and a thin as possible cutting disk. Then finished off with a file at the places where it was not quite split.

 

Forgot to say that before this I cut the web a little on the rear cover screw mount to be able to raise it up so that the screw hole on the carbon cover lines up when the cover is resting on the wire stand off spacers.

It works out that when the mount is level with the top of the silencer the hole is in the correct position.

 

The top section can now be removed and the mass of wire wool Chewbacca hair can be taken out also. It is spot welded in various places so I use an old chisel to release it in one piece as I want to put this back in later.

 

Once the wire wool is out you can cut out the internals. The coring projects I have seen before on different forums start from the top and work their way through all the tubes, metals walls and Cat until it is all cleaned out, but it is possible to remove all this in one go.
Using a 9" angle grinder it is possible to cut down through the shell at the inlet end approx. 5mm from the edge of the cut to remove the outer cover. The odd little bits that the grinder can't reach right through can be knocked through with an old chisel.
The at the outlet end grind through where the outlets are welded to the outer body of the silencer. Then with a bit of jiggery pokery the internals should be able to be removed (they are only welded in at each end).

 

Then clean out the Wire Wool and Chewbacca hair from the lower section to leave just the lower part of the silencer casing.

 

I while ago I bought some Flat Oval Stainless Tubing for this job so I cut two at the same angle as the original Termi can outlets and then cut off square at a length that would reach past the carbon cover and enough inside the silencer to attach the perforated tube.

There are only slightly smaller than the Termi outlets but pretty much the same proportions so should fill the cover holes nicely.

 

I then worked out the pitch between then so they would be central in the cover holes and welded a small strap across the top of them whilst I Ralph out the holes bigger in the silencer offering them up as I go.

Here they are tacked in place. (I kept checking the carbon cover also.)
I only have an ARC welder so I can only really tack the pieces in place so they can be welded up professionally with a TIG later. The ARC is way to fierce to do any more.

 

Here is a pic from the top with the Tubes in place.

 

Here is one of the Right Outlet tacked in place.

 

Here is the Carbon Cover fitted. Quite happy with the result and not a million miles off how the Termi looks. That is it for now but will try to get the perforated tubes in place soon then it can be filled with exhaust packing and TIG welded and cleaned up.

 

...and both the cored one and the Termi...

 

Cheers!
If it sounds right when its done I will probably make a few to sell as I have enough flat oval tube left.
I'll do some ride by sound comparisons with the Termi.
DD