Fitting a Hi-Flow Cat
It's a situation I'm sure many of you might have been in before. Getting rid of the stock catalytic converter, but wanting to keep a high flow cat for legalities.
I've got a Berk 3" downpipe and a Fujitsubo Legalis R, which provides a pretty free flowing exhaust, but it doesn't give much opportunity to keep a cat without hacking up some reasonably exensive parts. After a bit of searching around, and messing under the car, I came up with a decent solution.
This is the B pipe that comes with the Legalis R. I decided I wanted something to completely replace this, so that the exhaust was unmodified if I wanted to sell it later, and so I could keep a 'test pipe' for track days if needed. Although the Berk downpipe also has a flex section, this is before the solid supporting bracket so its effectively rigidly mounted to the engine. Fitting in a cat and flex section looked to be tricky. Furthermore, the B pipe is currently the lowest section of the car, which is already lowered, so I couldn't have it any lower and still have 100mm clearance.
I built a jig out of some scrap angle iron and some wood. The cutout in the centre shows where the engine sump sits in relation, so I could mess around with positioning and be sure it would clear everything.
The key was finding a cat which was pretty much perfect:
MagnaFlow 59979, 3" outlets, only 8" in overall length and one of the outlets is already angled. Ordered this, the shortest flex section I could find, and some pipe and flanges (a 2 bolt and 3 bolt)
Didn't take any pictures while fabbing it up, but I traced the mandrel bends onto some cardboard to make trial fitting it easier.
Excuse the dodgy looking welds, but this is how everything fit together.
Add a bit of paint to tidy it up, and its finished. In the end I'm really happy with the result. It doesn't sit any lower than the original B-pipe, so I maintain at least 100mm clearance. And I didn't have to hack up any of my existing parts.