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  1. #21
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    Citazione Originally Written by paolo159 Visualizza Messaggio
    confirming that it is a problem of variable geometry you've got it by the fact that after the removal of the dpf problems are increased with dpf most likely be the opening of the blades of the geometry was sufficient to generate the required pressure, in the absence of exhaust back pressure after the removal of the palette should open up more to compensate and may be blocked.
    this is not ? correct, if you remove a restriction on the pressure difference between the outlet manifolds and the environment increases, and this causes an increase of speed? of the gas. Pi? or less ? what happens (even if fi goes in the field of incompressible) when you raise the rail pressure, the injection time cala in parit? flow.

  2. #22
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    Hello Sandro,
    I don't want to contraddirti it be the controversy, ? only to discuss and better understand the operation, but I believe that it is only logical that by reducing the exhaust back pressure ? true as you say that you increased the speed? of the gas, but the prex in the turbine side of the exhaust ? pi? constant and generer? vacuums, just because? the drain empties more? quickly than to have the dpf, which is the "cap" and maintains a constant pressure, ? a bit the same problem that occurs after the removal of the cat.
    the variable geometry at this point will work? most (in terms of trips), and especially the pi? quickly to compensate for these gaps..
    What are you saying ? true in conditions of constant pace for example, if the engine is revolving at constant speed, e.g. 2000 rpm, then the geometry would be a little more? closed than before because of the greater speed? of gas leakage but to an important decrease of the rpm will be? forced to open more of the fins since? the drain empties easily.
    What I wanted to say in the previous post ? there? that occurs ? an increase in the delta of the pressures between 900 and 4000 rpm that make the geometry work the most.
    Then ? clear that if there are any other problems to the turbine having exhaust ir? ****** brings only benefits.

  3. #23
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    Citazione Originally Written by paolo159 Visualizza Messaggio
    confirming that it is a problem of variable geometry you've got it by the fact that after the removal of the dpf problems are increased with dpf most likely be the opening of the blades of the geometry was sufficient to generate the required pressure, in the absence of exhaust back pressure after the removal of the palette should open up more to compensate and may be blocked.
    best answer !! thanks
    The Alfa brera 2.4 jtdm '08 210 hp [direct exhaust +downpipe]

  4. #24
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    Citazione Originally Written by paolo159 Visualizza Messaggio
    Hello Sandro,
    I don't want to contraddirti it be the controversy, ? only to discuss and better understand the operation, but I believe that it is only logical that by reducing the exhaust back pressure ? true as you say that you increased the speed? of the gas, but the prex in the turbine side of the exhaust ? pi? constant and generer? vacuums, just because? the drain empties more? quickly than to have the dpf, which is the "cap" and maintains a constant pressure, ? a bit the same problem that occurs after the removal of the cat.
    the variable geometry at this point will work? most (in terms of trips), and especially the pi? quickly to compensate for these gaps..
    What are you saying ? true in conditions of constant pace for example, if the engine is revolving at constant speed, e.g. 2000 rpm, then the geometry would be a little more? closed than before because of the greater speed? of gas leakage but to an important decrease of the rpm will be? forced to open more of the fins since? the drain empties easily.
    What I wanted to say in the previous post ? there? that occurs ? an increase in the delta of the pressures between 900 and 4000 rpm that make the geometry work the most.
    Then ? clear that if there are any other problems to the turbine having exhaust ir? ****** brings only benefits.
    this seems fair to me, then ? well to specify that the "problem" due to the emptying ? mostly due to the fact that you must have? to calibrate the operation of the variable geometry, in a way that does not cause the oscillations in the boost pressure.

  5. #25
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    Citazione Originally Written by SandroMarciano Visualizza Messaggio
    this seems fair to me, then ? well to specify that the "problem" due to the emptying ? mostly due to the fact that you must have? to calibrate the operation of the variable geometry, in a way that does not cause the oscillations in the boost pressure.
    Then all the times that you removed the dpf it is necessary to calibrate the geometry ?
    The Alfa brera 2.4 jtdm '08 210 hp [direct exhaust +downpipe]

  6. #26
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    if we wanted perfection, just an overboost and then the pressure would drop immediately to the constant without too many oscillations, but since that's not ? an operation to be 5 seconds ? best to leave it original...

  7. #27
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    very true what he says Sandro, put a hand to the map vgt that controls the degrees of opening of the blades is not ? its very simple...if it opens too much, you will have a supply irregular and risks too many spikes at the top, if it opens too little highlight only the problem...
    usually if there are imbalances, particularly annoying is not it also touches on why? must be a work of precision, done gradually and intervening only in those critical points that cause the failure, all verified step-by-step from diagnosis

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