Odd Noise on Cold Start

[Silverfox42]

My July 14 B8 sounds like that. Wouldn't be keen on revs for about 30 seconds or so until the valves close and over run stops.

Mr RS5 did this too - made a hell of a noise with the ABT exhaust. My old B7 over-ran on cold but was not quite as loud as the B8.

The sound clip sounds normal and for the last 10 seconds or the valves have closed (and are competing with the key warning when the driver door is open!).

[S4WON]

Holy thread resurrection,
Yes, its normal
I also did a video of mine

[stowchenko]

Thanks for the quick responses all. I guess I will sleep easy tonight then! S4WON if you could mail me your vid I would be interested to hear it. Thanks again. Scott

[S4WON]

Np

Exhaust rattle on cold start
viewtopic.php?t=117224

[geoffdunk]

This noise that everyone is talking about that lasts fro approx. 20 seconds is normal at fully cold starts, its a fan unit that pulls in extra air.

Audi quite clearly state to NOT rev the engine but start and let idle until this extra noise is finished, I worry about the clip I heard as its obviously a cold engine due to the extra fan/induction noise and then the engine is revved.

The bottom line is that this noise is expected and perfectly normal.

[birdiemachine]

Secondary air pump to heat up the cats to improve efficiency gents, all good

[S4WON]

Improve efficiency or screw emissions tests?
I smell a new scandal!

[PetrolDave]

Improve efficiency or screw emissions tests?
I smell a new scandal!

Heat up the cats faster by increasing the oxygen content in the exhaust.

[PSB1]

It sounds like it's falling to pieces initially, then it settles. Doesn't bother me but I'm sure it doesn't help in the old "Check out the sound of my V8 on startup" at the golf club routine.