Strange resonance coming on boost...?

[AJP]

Hi

Recently had a new rev G dv, pcv and cam follower fitted to my k03 GTI and the car now performs nicely. The rev C dv that came off was split, unsurprisingly.

I've just noticed over the last couple of days that when on full/moderate throttle I can hear a high pitched whistle, very briefly, around 2000-2500rpm.

Now it's not a turbo whistle 'sss' sound, or an induction hiss, more like a whistle that you'd make yourself, there's an actual note to it. It sounds similar to that odd resonance you get with some intakes on the k03 engine. Yet I'm completely standard.

I'm wondering if there's a tiny boost leak somewhere. I'd imagine that before the new dv was fitted, the rest of the pipework wouldn't have seen enough boost to cause this, which explains why I'm only hearing it now!

So what are the other weak points with the k03 engine? Intercooler pipework?

[MrACD]

The intercooler pipes are known to leak via the rubber o-rings.

2 on the drivers and 1 on the passenger, well worth swapping.

Through the stealers the o-rings are surprisingly expensive 

[AJP]

Cheers for that mate. How expensive are we talking?

And are these on the ends of the actual cooler, or further along the pipework?

[MrACD]

Cheers for that mate. How expensive are we talking?

And are these on the ends of the actual cooler, or further along the pipework?

Got ripped a new one  , my local hit me for £23 for the 3. 

3c0 145 117h (x1) and 3c0 145 117f (x2)

From the intercooler to the connecting pipe (f) and connector to metal pipe (h) - drivers side.

Passenger - Intercooler to connecting pipe (f).

 

[Beej]

I too have the same sound (I think) going from your description, although, I replaced my dv with a rev g, but I have an airtec cooler and pipes fitted and running 2 / 2+ tune. I had the noise before fitting the cooler though, so I am presuming it's normal

[AJP]

You can actually hear the noise in this BCS Powervalve video, at 1:47, and in the in-car footage straight after.

I always attributed it to being a quirk of aftermarket inlets on k03 cars, but it'd be interesting to know if this car was on a standard intake. @nige bcs

[Beej]

Yeah, that's it!

[AJP]

Yeah, that's it!

You say you're a 2 / 2+, so presumably with an aftermarket intake - did you notice the noise with the standard intake?

[Beej]

Well no, but I changed from rev c dv to g at the same time installing the revo intake

[Beej]

It doesn't do it on full throttle, just half to 3/4, but more so in normal D mode (I'm dsg)

[AJP]

I'd love to know what's causing it. I can see it becoming irritating!!

[Beej]

It does irritate me a little, especially if I am trying to 'make progress' rather than booting it without people at the side of the road, or the car next to me noticing too much!

[GTIEagles]

It's definitely worth checking your intercooler hoses. My drivers side hose was weeping oil slightly on both ends. Managed to source genuine o rings on eBay for a tenner. Easy to fit. I couldn't really notice any difference after but it must have been slightly loosing boost as it was weeping.

[Beej]

Mine are good, as I thought it too may have been a leak

[AJP]

Yeah got to say my car pulls well and the power delivery is nice and smooth.

It had a good checkup as well as the new dv, pcv and cam follower when it was in at Statller last week, so I'd have thought they'd have picked up on any issues with the hoses/connectors.

Not saying it's impossible that I've got a boost leak, just seems odd that a few people are hearing this same noise.