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EGR and turbo help please

Discussion in 'A4/A4 cabriolet/S4 forum(B6 chassis)' started by Marko, May 1, 2008.

  1. Marko
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    Marko Member

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    [May 1, 2008]
    Some time ago there was a thread where many people had disconnected the pipe from the EGR, thus stopping it's operation. Less smoke is seen and in turn is deemed to lessen the carbon billed up. Anyway........

    I did this on mine but I had a constant whine like a droaning, I assumed it was the turbo spooling. I decided to keep the EGR connected but minimise it's use with VAGCOM.

    Standard % use when hot and idling is 59%. Minimum operation for EGR is 48% which I set it to. I noticed that the turbo whined alot at say 1500 rpm and has begun to hum slightly at tickover. I've experimented and whilst engine was running I changed the values; sure enough the whine stops when at factory setting, ie more egr use.

    I'm assuming it's the turbo I can here, I can't see it being anything else.

    Can anyone explain why this happens and is it best to keep the EGR in the greater setting to prevent possible turbo damage. Should the turbo spool on tickover at all? I'd rather have some muck than a blown turbo.

    Thanks for anyone who can help.

    Marco
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  3. TFSI
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    TFSI Born to Fish

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    [May 1, 2008]
    When EGR operates it takes exhaust energy away from the exhaust turbine thus slowing your turbo down. :yes:

    When EGR is not operating all the exhaust energy will drive the turbine thus speeding it up.:yes:

    50% Exhaust gas recirculation seems excessive the euro 4 engines (Diesel) i work with only recirculate 19%. :huh::huh::huh:
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  4. Marko
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    Marko Member

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    [May 1, 2008]
    I've just edited my post to reflect that the 59% is at tickover. I've graphed the values during a run and it does decrease to 4% when full throttle is applied.
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