Cobra exhaust

New Year's day (happy 2016 to all readers) and another few hours in the garage to tackle the exhaust system.

I laid out the various parts of the exhaust system so that I knew where to fix them. The system consists of various tubes, catalytic converters, a balance box on the central pipes, plus two Cherry Bomb silencers. I have already fitted the headers. The Cherry Bombs (silencers!!) will be fitted later, once the body is in place. The diameter of the Cherry Bombs is so big that I could almost park the every day car in them!

Exhaust system, less headers, laid out

What I realised after initially assembling the system on the chassis was that the gearbox mounting plate, which also acts as a point from which to support the exhaust system on my car, had been mounted (note how I don't take any blame here) on top of the chassis lugs (logical place?). However, it should have been mounted below to avoid the pipes touching the chassis - not the best engineering solution I have seen, but the four high tensile bolts should be fine as the weight of the gearbox tail and the exhaust system are not massive. Nothing about this location in the manual, so it was trial and error, mainly the latter.

Gearbox mounting plate above the lugs

Also, I had to open up the exhaust mounting hole a little to fit the threaded part of the bobbin from which the exhaust system is supported. So the mounting plate was removed yet again and bolted to the chassis from the underside. This time it was a little more difficult to get out, as the exhaust pipes were in the way! 

Gearbox mounting plate moved to below the chassis

By moving the bracket to the underside of the chassis it moved the exhaust mount about 12 - 15 mm lower, so giving clearance to the chassis. Heat Resistant silicone was applied to the system where the pipes joined to reduce any risk of blowing (hopefully).

The rear of the exhaust system was located using reinforced rubber and six bolts (as supplied by GD), three bolts (with shake proof washers) locate into the rivnuts in the chassis and three bolts go through the bracket and the rubber mount, secured by nyloc nuts. The rubber mount needed trimming to size and holes drilling.

Rear view of exhaust before rubber mount fitted

The bracket supplied keeps the pipes the correct distance apart and helps to locate them. This is only fitted hand tight, so was not supposed to be in the right location as supplied. Drilling the rubber is interesting. It seems to self-heal after drilling!

Rear exhaust mount fitted, the six fixings can be seen

Now all the clamps were tightened up to secure the system in place and the oxygen (lambda) sensors were fitted into each side below the headers. These will be wired in later.

Exhaust clamps below a header and with the lambda sensor fitted