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turbo question


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I really dont know much about cars. i wanted to know why is that the a4 has a turbo, but you cant hear the release when the clutch is in. unlike a twin turbo rx7 for example.. i think you know what im trying to say. the pssssssst sound. Let a dummy about cars in on this =)

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I'm not really the expert on this but it's all to do with the boost value I think. Most of audi's customers do not really want a great whoosh noise every time they come off the acclerator.!!

There are loads of after market valves that will cause this effect .. they also improve the performace of the turbo by releasing less or more pressure when required

Dave

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I think the turbo noise thing has something to do with whether the pressure is dumped into the air or back into the system. I'm no expert but if you put this post into the tuning forum I'm sure you'll get a more technical answer. A search of that forum will also probably give you the answer, I'm sure this has been discussed in there.

Hope this helps! beerchug.gif

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The release noise occurs when the Diverter Valve (DV) releases boost pressure, when you lift off the gas pedal - this released air is fed back into the elephant trunk-like air inlet hose, rather than venting it to the atmosphere like the traditional types (ie Escort RS Turbo and Nissan 200SX types) - this is why you don't necessarily hear the noise as much on VAG turbo cars.

The DV is required to keep the turbo spooled, otherwise you will have more turbo lag as the turbines take longer to reach operating speed when you next put your foot back on the gas.

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  • 2 months later...

[ QUOTE ]

The DV is required to keep the turbo spooled, otherwise you will have more turbo lag as the turbines take longer to reach operating speed when you next put your foot back on the gas.

[/ QUOTE ]This is correct...i just thought i'd explain why. If diverter valves weren't in place to release excess pressure, that pressure would have a tendency to go out the way it came in, giving the turbine the tendency to slow down to the point where it needs to spool up again. Also, sudden changes in turbine speed and direction can cause damage to the turbo. So with DVs, pressure is released in such a way that turbine speed isn't compromised. And by the time you shift into the next gear and step on the gas, the turbo will already be that much closer to "spooled up" than if it were slowed by back pressure.

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