borisivan

Hi,

Not having any other S5 around to compare it to, I'm wondering if my exhaust flaps are working correctly.

If I start the car before I shut the door (I'll have to verify the same thing happens with just the window open), I hear a very loud buzz/brrt for a second, about a second after the car starts. Think Bruce Willis from Die Hard -- "BRRT / Wrong answer, wanna go for double jeopardy where the scores can really change?" (or whatever he says there). Sounds like a bad relay.servo/actuator, and I was thinking exhaust flap.

This, and I only seem to see one flap working even when warmed up (in D / comfort). Living in NH, it's cold enough out already that even starting in the garage, the red line is in 'protected mode' and I can easily see exhaust only coming out of pipe 3 of 4 (if counting from the left). I assume that's the default cold start mode. But after a minute or so, the RPMs settle down and it's the time I'd expect one of the pipes on the left side to open up. No go.

After a 35 minute drive to work, (still in D / comfort), I left the engine running and got out and checked -- still seemed only like pipe 3 of 4, but it wasn't as obvious as the humidy/temp changed such that you couldn't see the exhaust, but I did a quick hand test and think it was only puffing out pipe 3 of 4.

So... first question is: is that loud BZZZZT normal that I described above? Second, does anyone know what exhaust pipes are supposed to be active under what scenarios?

luder888

I also noticed only my right pipes work when my car is idling in the garage. However I do see carbon build-up on both sides so I figured they all must work when I'm driving. I have my exhaust set to comfort.

N8!

Discussed many times - check this link:

https://www.audiworld.com/forums/sea...rchid=11347076

sand8

Correct, only the right one has the valve that switches between normal and sport mode. In normal mode, the right exhaust only uses one pipe. Sport mode uses 2, like the left side.