RS246.com Forum :: The World's #1 Audi R, S and RS Enthusiast Community

Hi

I am thinking of getting the Magnaflow high flow cat/downpipe to replace the stock cats, to go with the ECS h pipe which I got a couple of years back.

I have read to avoid an engine warning light I would need to weld an o2 sensor fitting to the rear of the cat and plug the provided hole just in front of the cat so that the o2 sensors are either side of the cat.

Anyone know/tried this or know different ?

Thanks

Basically, you have 2 sensors per bank. 1 sensor before the cats and 1 sensor between the precat and main cat.

If you are currently running standard downpipes and haven't got a stage 2 map then you will need to put spacers on the second lambda which sits just in front of the main cat once you have fitted the new high flow cats. This is not guaranteed to work though and ideally a stage 2 from the likes of MRC would be preferred as this removes the issue without the need of spacers

Track down/pm the member dufferdude, nice guy and I think he runs the exact setup in his RS4 with a sick sounding exhaust! My next upgrade.

Thanks for the replies. Sounds like I need spacers in the first instance.

If you get a stage 2 map that stops it think