Hi,

I figured I would post this here since there isn't much activity on the A5 forum and we share the same engine.

I installed my Spulen 3" DP and Hi Flow Cat recently and am wondering if this is normal. I Seafoamed by 2011 A5 using the technique here posted and I noticed I was pouring some white smoke out of my front o2 sensor. The front o2 sensor is on super tight, so I have no idea how it could be leaking.

Also to add to it I am getting a slight buzzing noise from my HFC/downpipe area when I gas it at a low rpm 1800-2400rpm once in a while depending on how I gas it, almost like a bee. I figured it was just extra turbo noise with the less restrictive HFC. I am not sure if the issues are related or not.

I don't notice any kind of power loss at all, FYI.

Any ideas?

Thanks in advance