A4-Freddy

I didn't notice this noise at first, but I was baby'ing the car a lot more a few weeks back too.

In 2nd and 3rd gears particulary, I notice a slight raspy/hissing/pinging noise as I accelarate through the 2-3k range. If I go very easy on the gas I don't hear it, but as soon as I get up on it a little I hear it start. If I get up on it more it becomes more noticeable. It fades out right around 3k.

The noise is very faint, hard to describe. Similiar to pinging noise I've heard on older engines when you jump on the gas in a gear too high, but it is more even and consistent.

I'm wondering if this is related to operation of the turbo? I read through one of April's links about turbo engine operation and was curious about wastegate operation and whether this would produce any noise. The noise kinda seems to coincide with the beginning of the noticable power boost I assume is coming from the turbo operation. Anyone else get this?

Nefilim

Are you using premium (91+) octane gas? If not, it might be pinging...

3.0 Dolphin

what does pinging/knocking sound like?

A4-Freddy

Using 91, yes. It is almost like a very low volume rattling. Sounds almost raspy. Hard to describe

J_J_Z

I have a new A4 1.8TQ a month ago same as yours. Just after break-in, I start to accelelate a bit. I have the exact same hissing noise as you describe.

Is your car still have this noise? Is it normal?