wagonface

I've just driven 2hrs to go on holiday and for the first time the turbo is whistling at me. I'm not sure if this is a very bad sign?

Symptoms:
I can easily hear the whistling in the cabin when the turbo spools up. As it goes from 0.0 to 0.7 the whistle gets louder. I am getting power from the turbo.

It's a larger than normal turbo. My seller told me it's a K29 hybrid turbo, but I don't know what that means having only hadthe car for 6weeks. I know the turbo was refurbished a few years ago (maybe 4?)

can anyone help? Being away on holiday I'm keen to find out if I am damaging anything by driving (I am not giving it the full beans until I know why it's whistling)

thanks for any help, josh

wagonface

The car is in for some bodywork and a service, and I wondered if anyone had any thoughts/advice on this? Symptoms are:
- boost guage always shows 0.1bar, even at startup and at idle revs
- turbo whistles as it spools up, audible within the cabin while driving (it didnt do this before)
- turbo is a K29 hybrid, and was refurbished 9yrs / 42k miles ago
- I found a note in the service history to say that the wastegate was repaired (by Ray Northway) in 2005, and Northway said at the time it might need replacing soon

Garage have had a look and reckon all the turbo piping is secure.

Anyone got an idea? Thanks for any help, Josh

Vifa

My boost guage shows 0.1 bar too (sometimes). I don't think you can do anything about this. But that isn't something serious anyway.

Are you sure the whistling noise is coming from the turbo ? I had a similar issue last summer, and it turned out to be some play in the alternator.

wagonface

Thanks for the reply. The alternator, spindle thingy and belt were changed at the exact time the whistle started... You might be on to something. I will get the garage to check.

Boeing 717

So does it whistle just when its spooling up and down or all the time??? It sounds like it could be an air leak maybe. My turbo is on its way to be rebuilt because i could hear it whining whenever it spooled up and down but not at a constant speed. The bearings are worn on mine. Your compressor and turbine wheel could also be rubbing on the housing. Check all your hose connections first.

ralt

I would say mine howls or moans more than whistles since I have owned the car. It did it before the turbo rebuild. It did it after the turbo rebuild. It did it before the engine rebuild. It did it after the engine rebuild. FYI its a K27. It runs. When it stops running, fix it.

Boeing 717

Yea howling and moaning i think is normal mine has always done that too. But the new noise i encountered was similar to when you blow into one of those wiz wheel toys when the turbo would spool up.

Kevin

Pull the inlet boot and look into the compressor housing. Take a flash light and carefully inspect the compressor wheel. They should be nice and straight.

A sound turbocharger will make a high pitch whine/siren as it builds boost. The wastegate will interupt that sound.

If you have a pressure side intake leak you will get all sorts of noise.

If you find any oil puddling inside the ducting and compressor housing you will need another rebuild.

wagonface

Thanks for all the replies. The turbo only started whistling and showing 0.1 on the guage after the garage fitted the new alternator and also a new rear blower motor. So part of me is thinking: "well it didn't whistle before so why is it doing it now". I'm Also pretty sure it is the turbo cos there is no whistling until 3.5k revs. It starts whistling as boost comes on and the whistle intensity increases as boost increases. The whistle remains constant if the boost remains constant.

I will see what the garage say, and if they are stumped I will tell them kevin's suggestion.

fritz k.

as the guys wrote the´re a few possible causes.

but checking the charger is not a big thing. remove that hose (pic) and you´ll have access to the axle. you can feel bearing clearance in both ways, should be no more than 0,6mm (radial) or 0,2mm (axial).

by spinning the axle your´e able to check whether the turbine moves free or already contacts the housing.

it is recommended not to drive with a possibly worn charger. consequential damages could cause way higher costs than renewing the bearings.

fritz

budge96

That almost sounds like a weak waste gate spring releasing pressure before it's warranted..
if a p[rior service determined the wastegate may require service soon that gets my vote, the pressure release will sound like a whistle psssst,pssssst psssst!
Particularly since thr PO has installed a higher rate turbo the wastegate may not be up to the task, Bert

wagonface

Thanks Bert - I'm no expert on this, but would a weak wastegate spring also tally with the guage showing 0.1 even when its just idling immediately after starting the engine?

If it is a wastegate issue, do people get them repaired, or should I just fork out for a Tial, which seems to be the choice for most people?

Thanks for any help, Josh

Megatron-UK

No, that's down to the digital gauge being rubbish

The Porsche part is an absolute fortune (not to mention huge and heavy!) - if you can even find one. You're better off with a Tial or Tial copy, all of which are rebuildable and probably 20% of the price of the original part. I'd also reccomend that if you want to run more than the standard level of boost, you fit a relatively weak spring in the wastegate (say 7psi / 0.5bar) and instead use an electronic or mechanical boost controller to increase the boost to your desired level - much simpler than fiddling about changing springs and shims in the wastegate.

al 965

A lot of high performance turbos make a whistling noise. My GTK Turbonetics ball bearing turbo whistles all the time and if I put the zork on it it is pertty loud @ idel. really sounds cool . Eddie Bellows car whistles real loud @ idel and as it drives away it sounds real good as it whistles with his dual ball bearing turbos with straight zorks. I have heard some LS vetts w/dual turbos that whistled real loud.

wagonface

Thanks for everyone's help with this. I think it is now resolved (I live in a city so haven't had a chance to really stretch its legs yet). How?

1) Indy decided it was the fan rubbing against the housing (recall that the whistle started after the Indy fitted a new alternator). So he removed the fan and skimmed it. Gave me back the car with the whistle still there (he is also in a city so said he couldn't replicate what I was hearing as he couldn't give it full beans to get the turbo going).
2) I gave it back to him. He then decided to "pressurise the system" and found that the pipe from the intercooler was loose at the bottom joint (I'm not sure what it joins onto). This had come loose when he removed the intercooler to fit the new alternator.