Can you hear your turbo?

4.2 V8 40v biturbo - 450 bhp
4.2 V8 40v biturbo - 480 bhp (plus)
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Ben_r1
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Can you hear your turbo?

Post by Ben_r1 » Mon Apr 16, 2018 12:12 pm

Since the weather has finally turned in the UK and we had one rare sunny weekend I broke the RS6 out of the garage for a Sunday blast.

Not sure I’ve ever driven it in anger with the windows down before but first thing I noticed was a strange rumble that seemed to rise and lower in volume precisely with turbo boost pressure.

I’ve had many a turbo car in the past and know that even with OE air boxes and recircs the turbo whistle is still audible albeit quiet.

Is this a normal noise or root for concern? It doesn’t sound like a whistle almost exactly like one of the aux belt pulley bearings is rumbling except it’s silent off boost and comes in with the turbos and also seems to be specific to the drivers side but could just be because I’m sat there?

My last MRC health check last month both front coolers were reported ‘slight leaks’ had one progressed to a more severe state perhaps? Turbo on its way out? Car boosts well and pulls very hard still, no loss in performance and no warnings on dash.

Advice, suggestions, comments? Thanks.

benh999
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Re: Can you hear your turbo?

Post by benh999 » Mon Apr 16, 2018 1:43 pm

Sort your coolers out... any boost leak will work turbos harder... Airtec rebuilt mine and they are bang on now with new cores...

Ajc
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Re: Can you hear your turbo?

Post by Ajc » Mon Apr 16, 2018 5:41 pm

You shouldn't have a rumble from a turbo , to me that would imply it's really not well at all .
Is it using oil ? . Maybe worth pulling the bottom ic pipes add see if you have oil in them .
Cheers Al

04 c5 rs6 , Ebony Black, Bare shell repaint , Milltek's, PSS9's,Hotchkis Arb's,Gutted precats, hybrid turbos, Bosch 044 ,And an annoying EML light

Mark-RS
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Re: Can you hear your turbo?

Post by Mark-RS » Mon Apr 16, 2018 7:21 pm

I can hear sucking noises from mine, but nothing that resembles a rumble....

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Ben_r1
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Re: Can you hear your turbo?

Post by Ben_r1 » Tue Apr 17, 2018 12:51 am

It’s not so much a rumble like a failing wheel bearing its hard to explain, a very deep bassy whistle.

I took the plunge and ordered a set of Wagner’s anyway, they need doing regardless so will fit them and see if it cures it.

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Nobby
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Re: Can you hear your turbo?

Post by Nobby » Tue Apr 17, 2018 12:02 pm

Can barely hear mine. Standard inlet with ITG filters. Exhaust does have a slightly whistle when the valves are opened otherwise no.
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Shoppinit
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Re: Can you hear your turbo?

Post by Shoppinit » Tue Apr 17, 2018 3:25 pm

Only time I heard my turbo was when the IC hose popped off in the absolute middle of nowhere in France. Then a lot of swearing as I realised the car was too low to do anything about it. Had to drive to the nearest village to beg the only bloke with a lift to let me lift the car and put it back on.

Even then you mostly hear the rush of air, rather than the turbo.

Probs your problem is the swiss cheese OE IC.
Daytona RS6 C5 Avant. Viper'd, Billies, Waggers, MTM box brain, C6 stoppers, xcarlink, R8 coolant cap (woohoo)
///M3 E46 -- XC90 (V8, natch)
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MattV8
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Re: Can you hear your turbo?

Post by MattV8 » Tue Apr 17, 2018 4:02 pm

I blew a hose off on my old saab once - same problem as you, it was too low to get to to put it back on. Managed to coax it back home by starting it and it firing up on the pre-start injector squirt, quite a lot of throttle flapping (to keep it running on the accelerator "pump" squirt) and even a bit of rolling bump starting, which I didn't think was possible on an auto - but snicking it from N into D got it going again a few times.

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Shoppinit
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Re: Can you hear your turbo?

Post by Shoppinit » Tue Apr 17, 2018 4:55 pm

You can roll start an auto (well, an old one at least) as long as there is still fluid pressure. If it just stalled then you can do it, but not if the pressure drops too low. You've only got a few seconds.
Daytona RS6 C5 Avant. Viper'd, Billies, Waggers, MTM box brain, C6 stoppers, xcarlink, R8 coolant cap (woohoo)
///M3 E46 -- XC90 (V8, natch)
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at and repair."

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