Hey guys, this could be partly because ive not driven the car with the windows down before (been to cold)

But on my way home from work today I noticed that when you build the revs up a bit and back off the Accelerator I get a slight fairly quiet Hiss noise, The sort of Noise you would get from a Dump valve? but quiter.

Is this normal? do they all do it?

Thanks in advance, pete

TDi or TFSi?

I notice one on my TDi VRS, a slight dumpy sound.

TFSi

Its very slight but there, had the car 3 months not noticed it until now but normaly driving with radio up and windows closed...

I presumed it was the turbo, but then i'm not very technical!

I have not noticed it on mine, but the exhaust sounds better with over 21K on it

Never heard the exhaust on my MKI....

Reckon Its something I should get looked at then? Just incase?

I would say that was normal.

My Mk1 did it standard and now with a DV and CAI its just a hell of alot louder.

Would it be the excess charge air being released between the turbo and the engine when lifting off the throttle? The engine wouldn't like all that extra air entering the engine with no extra fuel so it is released when the throttle is backed off.

You don't get that loud 'whoosh' because there isn't an external dump valve, I believe the excess air is internally relieved but I am not hugely in the know about the TFSI engine.

I get the same hissing on my TDI if you lift off when the turbo is loaded up.

Would it be the excess charge air being released between the turbo and the engine when lifting off the throttle? The engine wouldn't like all that extra air entering the engine with no extra fuel so it is released when the throttle is backed off.

You don't get that loud 'whoosh' because there isn't an external dump valve, I believe the excess air is internally relieved but I am not hugely in the know about the TFSI engine.

I get the same hissing on my TDI if you lift off when the turbo is loaded up.

That's about what I was thinking; very eloquently put.

I get a definite amount of whooshing and hissing at low throttle/rpm on my TDI amplified by the fact I'm using an Induction Kit as opposed to the OE airbox (which I'm sure must muffle things).

That's about what I was thinking; very eloquently put.

I get a definite amount of whooshing and hissing at low throttle/rpm on my TDI amplified by the fact I'm using an Induction Kit as opposed to the OE airbox (which I'm sure must muffle things).

Nice to know i'm not talking cobblers

I noticed a big difference between the OE airbox assembly and the K&N kit, there is much more piping on the OE setup so that would account for the reduced induction noises. Any induction noise is most noticeable with the passenger window down whilst going past a large brick wall or similar

Petey099, you have nothing to worry about, your car sounds normal.