PwrDriftr

If you rev the engine while in neutral, do you get the sound?

K04-S4

You should not be able to hear a true DV. Are you running a Blow Off Valve?

davidj24

I'm running a forge splitter it's the 50/50 dv. And I still have to check an see if the sound is made while revving it.

PwrDriftr

If your car does not make the sound while revving in neutral, you may have some kind of suspension problem.

davidj24

I took the car out. Tried to see if it would make the noise in neutral and it didn't so I took it for a spin around the block but didn't hear anything. When I got back I popped the engine and it felt pretty hot coming from the exhaust/turbo side (left side of engine bay) i dont know if this is normal? does the car heat up this quickly? another thing is I have a cel because my coolant temp sensor isn't working. Could the temp sensor be causing this weird sound or does it sound like maybe my engine is blowing? I'm afraid of this because there is a little rattle from the top when car is idling

PwrDriftr

Were you driving aggressively. Turbos do get hot. Considering the "quack" noise, the CEL for the coolant temp sensor and the strange rattle when idling, I think it's time for a quick trip to the mechanic for an inspection. These could be symptoms of a serious problem.

Jb20th

If the forge is a piston diverter valve they need to be serviced, the piston needs to be cleaned. They stick sometimes.
If the sound comes on when stepping on the gas and can be modulated by letting up on
the gas the valve is a good place to start. If the valve is sticking the charge air is not being released into the air intake. Causing turbulence at the turbo therefore your honking noise.
Anyway goodluck I hate annoying car noises.

K04-S4

Suggest replace the Forge 50/50 with a true Bypass Valve that does not vent. Your not doing the engine any favors by blowing off metered air meaning engine repeatedly runs momentarily rich every time the forge vents. Even though it does not trip a CEL due to the amount of vented air being within Motronic software limits, venting is not a good thing for a closed loop system.

davidj24

Update. Okay so I dissconnectdd the battery for a few hours when I connected it I lost the cel and found out that the sound comes bak when the thermometer is about half way. It a loud noise even sounds a bit like a loud whip. Also I have a friend with a stok dv frm his sabb 9-5 I was wondering if it'll work on my a4