headers/high flow cat questions
 

I did a search and found some posts but they didn't answer my questions. I currently have aftermarket headers/cats on my S. Bought them used so don't know the brand. These are the type where the header/cat is one piece ( welded together ). I then have aftermarket rear delete pipes and then a Dansk banana muffler. Dyno numbers show I had a boost in performance. I have no issues with the current setup. But in the back of my mind I really don't care for the one piece design, I know at some point a cat will go bad and now the header/cat have to be replaced. Not a good design in my opinion. So has anyone gone with more conventional headers with a bolt flange and adapted a cat with a similar flange ? I know it's tight working in that area of the car but with " spun " housing cats the fitment might be easier. Doing a search of spun type cats a 2 " in/out is aprox. 11 " long and you might be able to trim a little off the length. And obviously there is some length to be had as far as adjusting in the rear cat delete pipes. Most Porsche 986 headers have an O2 bung so the front O2 sensor should be no issue. The rear O2 sensor wiring " may " have to be adjusted to add a little length. And finally here in GA. we do not have tail pipe sniffers but the county I am in has a " emission " test which is just reading the ECU for recent failed codes. But I still want to be somewhat green in my approach. It looks like there are quite a few spun housing cats in 200 or 300 cell count ( not ceramic type ) for the $100.00 range. Weld a three bolt flange to it and bolt it to the header. So what do you think ?

The set up you describe is common in UK and Europe. I have cat less headers and 100 cell cats where you US guys have the secondary cats or cat deletes as you call them. With some good buying this cost me less than US$350

EDC do your cats bolt to the headers ? Or are your cats further downstream ? Any pictures of your setup ? Any issues with fault codes with the 100 cell ?

It is a pretty standard set up for any UK car. The headers as standard have no cats on a 986. The cats bolt up to the exhaust and headers no problem. My aftermarket cats are the same fitment as the standard ones. They do throw a CEL light but a remap will map out the rear lambda sensors. They pass the UK MOT emissions fine. Any photo of a UK or most European cars will show the fitment.