Tuesday 18 January 2011

Exhausting progress




I started on the downpipe and measured up for some tubes. The word is that turbos need as little back pressure as possible, so the reason for the big downpipes.

The outlet from the turbo is 70mm (2.75in) downpipe, so it made sense to match that. So I measured up and worked out what I needed. The plan was to reuse the existing silencer (which is big and heavy but nice and quiet) which is 2inch input. So I bought a couple of 45degree 70mm bends. Once these arrived I realised that in my calculations I hadn't accounted for the length of the bend and there wasn't sufficient space before the silencer. So, order new silencer from Jetex which is a bit shorter, and slightly larger bore (2.5inch, you can't get them in 2.75in), and a 45deg bend in 2.5in for the tailpipe.

To get the 70mm down to the silencer I cut 2 8inch long wedges from the bend and then closed that up with a couple of exhaust clamps and then welded it together. I am not much good at welding, but by putting an aluminium tube under the weld means that burning through isn't a problem and the backing reduces the need for purging the weld from behind (something I don't have the luxury of).

After loads of cutting, welding, measuring, grinding etc I ended up with this.

I need to clean up the weld in the middle of the downpipe and weld the downpipe to the flange.


Finally I bolted it all up, welded up a support bracket with a captive nut, and modified the tailpipe to allow it to exit from the side of the body (its great being able to weld, even if I am rubbish at it).

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