Yes, that's it. Loud obnoxious jet-engine-like noise lasts for 30-40 seconds after start, then goes away when idle speed drops. Audi attributes it to the design they created for this engine to force air to the catalytic converter to help reduce emissions (as best I understand it). I've been told that the separate pump that quietly accomplished the same in previous designs, has been eliminated.

With regards to Poppy's 'reassuring' post above....Toyota just released service bulletins saying sudden acceleration in Camrys and brake failure in Priuses is 'normal' too! It's a flawed design, dude.

 

Flawed design...yes, I am pretty sure we all understand it is a flawed design, otherwise we wouldn't have a thread discussing it. The simple fact that it is entirely too loud may or may not have any bearing on whether or not the pump is more likely to fail...dude...

 

I am somewhat reassured, but will remain watchful. I'll just tell everyone that it is the "Turbo warming up" to avoid long explanations of the purported cause.

 

So I also experience the same noise from 09 audi b8 quattro upon cold start. Just wondering is there any this issue can be addressed?