Effect of boost leak on boost pressure

[McDub]

In the last couple of days i've heard a strange whistle sound when boost gets to 10psi and over (i'm chipped and it will boost up to 17-18ish)
I was thinking it sounded like a small boost leak escaping out of a small hole sort of sound, hence the whistle...
the car still seems to boost fine, though hard to say. but it seems maybe a tad slower.

so the question is, can you have a boost leak, and still get to your top boost pressure?
the way i see it, say you boost up to 18psi, couldn't the turbo still boost the pressure up that high, and all that you're loosing is flowrate, rather than pressure, i.e most goes through the throttle body, with a bit leaking out a tear or bad seal.
of course this would depend on how bad the leak is i suppose...


the sound is predominantly to the right side of the car (windows open) as you'd expect... i can't hear a vacuum leak at idle...
the sound is basically the sound of the normal airy turbo spool up sound, but just with a subtle whistle... not sure what to do about it!

[McDub]

no thoughts?

maybe it's just the turbine getting a little noisier with age, or perhaps it's turbulance of the exhaust passing throught he wastegate as it opens up to bleed off a bit of exhaust...

[noone]

If you have a boost leak, it does not have to slow your car to a stop, it could be very minor, but loud enough to hear.

As with many things to do with your car, you can do some logging to see whats happening - Vag Com.

Last boost leak I had was a hose clamp that needed a bit of tightening.

Have you replaced your diverter valve? What mods have you done?

[fuzion]

In the last couple of days i've heard a strange whistle sound when boost gets to 10psi and over (i'm chipped and it will boost up to 17-18ish)
I was thinking it sounded like a small boost leak escaping out of a small hole sort of sound, hence the whistle...
the car still seems to boost fine, though hard to say. but it seems maybe a tad slower.

so the question is, can you have a boost leak, and still get to your top boost pressure?
the way i see it, say you boost up to 18psi, couldn't the turbo still boost the pressure up that high, and all that you're loosing is flowrate, rather than pressure, i.e most goes through the throttle body, with a bit leaking out a tear or bad seal.
of course this would depend on how bad the leak is i suppose...


the sound is predominantly to the right side of the car (windows open) as you'd expect... i can't hear a vacuum leak at idle...
the sound is basically the sound of the normal airy turbo spool up sound, but just with a subtle whistle... not sure what to do about it!

The list i would check.

Take inner guard off (Driver Side) - Check hose clamps on intercooler and charge pipe up to turbo.

Check elbow from charge pipe to turbo (up top engine towards firewall if your not sure)

Check your Vacuum Hose from Fuel Pressure Reg, change if still OEM as the oem ones are **** house and break easily.

Diverter Valve is a must, you do need to change it if its stock however it would NOT make a whistling noise it would just not hold pressure and leak on boost and give a flutter sound fi stock if its gone.. not a quick snap.

Throttle Body Hose i'd check that as well, and of course air intake and have you changed your Turbo Inlet Pipe (TIP) as if you have they do have a tendency within a year of fitting to pop off SOMETIMES.

My Elbow from Charge Pipe (i/c pipe up top) to Turbo pops off and lately a lot due to running so much boost on the full tune. When that comes off, car dies altogether lol... oh fun times!

That'd be my list..

All else fails and your still unsure, you're welcome to pop by and ill have a squiz through it all for you

[noone]

My Elbow from Charge Pipe (i/c pipe up top) to Turbo pops off and lately a lot due to running so much boost on the full tune. When that comes off, car dies altogether lol... oh fun times!

Are you still running the K03s Pierre? What boost are you running?

[McDub]

thanks for the advice pierre
i took the guard off, so much dirt on the backside of the car chasis!

hose clamps seem fine from the turbo to the intercooler, i gave them a little tighten just incase.
I noticed a lot of oil on the underside of the rubber hose that connects the pancake pipe to the turbo. is that normal?

I've decided while i'm at it, to flush out my intercooler so i got some carby cleaner just now, so time to try get the front bumper and headlight off!

And yep i have replaced my diverter valve, i've got the apr R1.
and yes i've also replaced the TIP recently, and was sure i did it up tightly to the turbo (was a biatch to get on!!!), but will check that as well.

Oh btw i couldn't here this whistle sound at all today.... it seemed to dissapear within a day, no doubt it will return.

btw i'm not sure which pipe you're calling the "charge pipe"?

[McDub]

well that was a complete waste of time taking off my intercooler, not a drop of oil in it...

although i found something suspicious: http://www.vwwatercooled.org.au/newf...ad.php?t=42810

i was following this tute http://forums.vwvortex.com/zerothread?id=3269395 and it says to remove the harness... maybe its for american cars only?

edit: yes it's the boost sensor, googled the part number. all good then. funny how we still have the sensor, just that it's not wired up!