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Difference between dump valve and diverter valve

Discussion in 'Tuning' started by imported_Wicked666, May 2, 2005.

  1. imported_Wicked666
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    imported_Wicked666 Guest

    [May 2, 2005]
    What is it? I know I have an AMD diverter valve fitted and i know it releases air but what would a dump valve do differently?

    This may be a really simple question but i don't know. wasn't interested in engines on my old car, just ICE.

    Thanks
    #1
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  3. Ryanc
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    Ryanc Active Member

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    [May 2, 2005]
    dump valve/diverter valve essentially the same thing. Obviously the stock valve re-circulates the air back to the intake while a atmospheric dump valve,dumps it too the air.
    #2
  4. Ess_Three
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    Ess_Three Active Member

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    [May 2, 2005]
    Yeah, one dumps the air to atmosphere, makes a silly noise like some chavved up Impreza, and loses 5-7 BHP on each gearchange in lag...
    The other is a modern solution to keeping the compressor spinning and maximising performance....

    Pshhht. Every RS Turbo / Impreza owner will love you. Everyone else will think you are a tos#er.
    #3
  5. Online

    Guest

    [May 3, 2005]
    Like the others say dump valve releases it into the atmosphere - hence the noise. Where as a diverter valve re-circulates it - meaning less loss of power.

    As far as i know the audi turbo engines really don't like dump valves so stay away from them.
    #4
  6. imported_Wicked666
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    imported_Wicked666 Guest

    [May 3, 2005]
    I shall be sticking with the Diverter Valve i think. Thanks for the input. Now I can tell my mate why my car doesn't (and why I won't make it) go psssst!

    I'll just overtake them all and be too far away for anyone to hear anyway!!
    #5
  7. OutLore
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    OutLore VOIP Dude

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    [May 4, 2005]
    [ QUOTE ]
    Pshhht. Every RS Turbo / Impreza owner will love you. Everyone else will think you are a tos#er.

    [/ QUOTE ]

    /ubbthreads/images/graemlins/beerchug.gif /ubbthreads/images/graemlins/lol.gif
    #6
  8. gc48067
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    gc48067 Member

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    [May 5, 2005]
    Fitting a cone filter (such as a K&N 57i kit) gives you both a little noise from the DV and retains the stock setup - ie closed loop.

    Basically you can hear the DV operating.

    Greg
    #7
  9. imported_VaulterTim
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    imported_VaulterTim Guest

    [May 6, 2005]
    It certainly does...

    Both types of valves actually make the same noise because ultimately they are releasing excess boost pressure.

    The only difference, as pointed out above, is that one releases to atmosphere so it can be heard and the other releases back inside the intake pipe which means it is sound-proofed to some extent.

    If you remove the sound-proofing, in most cases this will be your entire airbox, and as Greg suggests fit a cone filter in lieu of it, then you will hear the 'Diverter Valve' releasing boost just like you would hear a 'Dump Valve' releasing boost.

    So as everyone says, they are essentially the same thing.

    Cheers

    Tim
    #8
  10. Mcgough
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    Mcgough Member

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    [May 15, 2005]
    Any idea on which kit to buy and where from for a decent induction noise and no damage!!

    for a 1.9 Tdi (tuned to 175BHp)
    #9
  11. foolish3uk
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    foolish3uk Member

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    [May 19, 2005]
    here we go again about dump valves, my a3 never lost power whilst running a atmospheric valve, not even one BHP rolling roaded and was running perfectly!

    im not even going to argue about it!!

    sounds nice with 57i induction kit, got it from motormania. but a guy is selling raid induction kits on ebay, may be worth a look!
    #10
  12. Ess_Three
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    Ess_Three Active Member

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    [May 19, 2005]
    [ QUOTE ]
    here we go again about dump valves, my a3 never lost power whilst running a atmospheric valve, not even one BHP rolling roaded and was running perfectly!



    [/ QUOTE ]

    Nobody said it would on a rolling road...as the run is done in a single gear.

    The engine loses power between gear changes as the turbo has more lag...lag = power not being made.

    I'm not going to argue about that...it's fact.
    Why do all the manufacturers of sophisticated engine managed turbo engines use closed loop DVs?
    Obviously, because they offer no gain...
    #11
  13. dcallaghan
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    dcallaghan Member

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    [May 31, 2005]
    There has been a lot of arguments on AS about DV vs DVs.
    Lets have a think what is happening when you change gear in a turbo engine:

    1. Under acceleration the engine is producing lots of exhaust, spinning up the turbo and supplying pressurised air (more oxygen by volume) to the inlet
    2. Now you lift off and depress the clutch to change gear
    3. The exhaust pressure and flow disappears and the turbo is spinning like a flywheel
    4. We now have a positive pressure between the inlet turbine and the engine and a lower pressure between the inlet turbine and outside atmosphere. Thus air will try to flow backwards through the inlet turbine, which will stall it (because the exhaust turbine has no force acting on it to keep it spinning)
    5. To prevent stalling the turbo, the DV exhausts pressure in the inlet manifold either to atmosphere or back to the inlet side of the turbo.
    6. A 'Diverter Valve' exhausts to the inlet side of the turbo, which is open to the atmosphere, so the best it can do is equalise the pressure across the inlet turbine
    7. A 'Dump Valve' exhausts to atmosphere, meaning that the best it can do is equalise the pressure across the inlet turbine.

    Thus, there appears to be little difference in actual effect and I would conclude that manufacturers dump the excess into the inlet side of the turbo to reduce the noise. Basically, the air inlet side of the turbo IS atmosphere (with a pipe on it).

    Rally cars use the brute force method of stopping compressor stall, they simply explode some fuel in the exhaust, keeping the turbo spinning and the pressure across the inlet turbine positive.
    #12
  14. ianhg
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    ianhg Member

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    [May 31, 2005]
    [ QUOTE ]
    here we go again about dump valves, my a3 never lost power whilst running a atmospheric valve, not even one BHP rolling roaded and was running perfectly!

    im not even going to argue about it!!

    sounds nice with 57i induction kit, got it from motormania. but a guy is selling raid induction kits on ebay, may be worth a look!

    [/ QUOTE ]

    i have an Iduction kit on my S3. its hidden in the airbox. you can hear the nice whoosh of the DV but only if ur close to the car or inside of it, its not annoying for passers by,
    #13
  15. dcallaghan
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    dcallaghan Member

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    [May 31, 2005]
    [ QUOTE ]
    hmmm,i was also under the impression that it was dumped turbo side of the maf so the air/fuel mixture was correct,if the air is dumped to atmos then technically it's unaccounted for.

    [/ QUOTE ]

    Can someone look where the output of the standard diverter valve exhausts to exactly? I dont like messing my nails up!
    #14
  16. imported_Wicked666
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    imported_Wicked666 Guest

    [May 31, 2005]
    [ QUOTE ]
    There has been a lot of arguments on AS about DV vs DVs.
    Lets have a think what is happening when you change gear in a turbo engine:

    1. Under acceleration the engine is producing lots of exhaust, spinning up the turbo and supplying pressurised air (more oxygen by volume) to the inlet
    2. Now you lift off and depress the clutch to change gear
    3. The exhaust pressure and flow disappears and the turbo is spinning like a flywheel
    4. We now have a positive pressure between the inlet turbine and the engine and a lower pressure between the inlet turbine and outside atmosphere. Thus air will try to flow backwards through the inlet turbine, which will stall it (because the exhaust turbine has no force acting on it to keep it spinning)
    5. To prevent stalling the turbo, the DV exhausts pressure in the inlet manifold either to atmosphere or back to the inlet side of the turbo.
    6. A 'Diverter Valve' exhausts to the inlet side of the turbo, which is open to the atmosphere, so the best it can do is equalise the pressure across the inlet turbine
    7. A 'Dump Valve' exhausts to atmosphere, meaning that the best it can do is equalise the pressure across the inlet turbine.

    Thus, there appears to be little difference in actual effect and I would conclude that manufacturers dump the excess into the inlet side of the turbo to reduce the noise. Basically, the air inlet side of the turbo IS atmosphere (with a pipe on it).

    Rally cars use the brute force method of stopping compressor stall, they simply explode some fuel in the exhaust, keeping the turbo spinning and the pressure across the inlet turbine positive.

    [/ QUOTE ]

    the plot thickens.....

    interesting reading. Thanks for that. This thread should clear the matter up once and for all! /ubbthreads/images/graemlins/grin.gif
    #15
  17. ianhg
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    ianhg Member

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    [May 31, 2005]
    [ QUOTE ]
    [ QUOTE ]
    hmmm,i was also under the impression that it was dumped turbo side of the maf so the air/fuel mixture was correct,if the air is dumped to atmos then technically it's unaccounted for.

    [/ QUOTE ]

    Can someone look where the output of the standard diverter valve exhausts to exactly? I dont like messing my nails up!

    [/ QUOTE ]

    open your bonnet and have a look, you have your airox on the right hand side with the Maf coming out of the left of it with a plug on it, the turbo pipe then curves down behind the engine, the DV puts the air into this turbo intake pipe just between the turbo and the maf
    #16
  18. PaulRS3
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    PaulRS3 Well-Known Member

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    [May 31, 2005]
    yes standard DV dumps after the maf, before the turbo.

    so the maf does indeed know (and already measured) that dumped air is in the system for fueling.
    #17
  19. leezace
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    leezace Member

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    [Jun 2, 2005]
    Yawn..........
    #18
  20. Ryanc
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    Ryanc Active Member

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    [Jun 3, 2005]
    i'm sure someone has logged on afm type cars the mixture going from lean to rich when using a atmospheric dv rather than a standard recirc.Stick with the stock system is there any other reason to change?
    #19
  21. Ess_Three
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    Ess_Three Active Member

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    [Jun 7, 2005]
    Typical...just as a thread starts to get interesting, with geniune information being offered...the cretins feel obliged to spoil it.

    I've dumped all the idiotic replies in the bin...and for the record, I (and the other mods) have just about had enough of all this petty **** that's going on...so from now on...excessive posting of unrelated **** will result in your user name being changed to 'idiot', 'thicket', 'dunce' or similar...and a week long ban for my inconveniance of having to deal with it.
    OK? (not that I give a toss if it's not!)

    Toe the line Gentlemen...this thread was just getting interesting to those of is with an IQ larger than our shoe size...

    We shall continue now...
    #20
  22. Ess_Three
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    Ess_Three Active Member

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    [Jun 8, 2005]
    Leezace won't be joining us for some time, Gentlemen.
    If at all...

    So, anyone else want to lock horns with the Moderators?

    There's plenty more room on the banned list...

    As you were...
    #21
  23. Ess_Three
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    Ess_Three Active Member

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    [Jun 9, 2005]
    Let's get a few things straight...

    This Forum is heading downhill. It's being subjected to the irrelevant posting of smileys at any opportunity...and post whoring of the worst standard....no doubt to boost post counts.

    The process of stopping this **** starts now.

    We - the moderators - are fed up with it.
    We have had enough complaints from enough genuine users to make a stand.
    This, Gentlemen...it it.

    I have no issue with banter...no issue with playful insults...and no issue with heated discussion provided it is heated with good reason...i.e. the facts are being put straight....I also have no issue with sarcasm.

    This Forum used to be a place where great information was spread around...not it's diluted and many users are not joining in because of the way good threads get spoiled by fools.

    So...we are going to do something about it...

    In the case of the DV vs Dump Valve thread...I removed all the irrelevant posts as they were diluting a very informative thread.
    These reasons were given in my post directly after removing the ****.

    I also stated that from that point forward...we would stand for less of it.

    This was crystal clear, for all to see.

    My reasons were for the greater good of all the genuine people who were taking something from the thread.
    What happens when one of the Mods make a decision for the good of the forum?
    They get a slating...as I did.
    Moderators do this job for nothing…giving up their free time…it’s a thankless task and one we do not take kindly to being insulted for doing to the best of our ability.

    Well...it doesn't take a genius to work out that if someone takes on a Moderator who is doing his job and attempting to uphold the rules of the forum...he's backing a loser.

    The reasons were made clear...I asked people to toe the line...certain individuals chose not to.

    That is a battle they will not win. We have a 'Ban User' button...
    The time has come to get some decorum back into this place...it starts now.


    I am asking people to uphold the rules of the Forum…by all means continue to enjoy playful banter, but do not spoil informative threads.
    #22
  24. dickys3
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    dickys3 Moderator Staff Member Moderator

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    [Jun 9, 2005]
    Totally agree with Glen here.

    We get many complaints from forum members on here regarding mindless posting and "post whoring" in general.

    We have also mentioned many times before that this needs to be stopped, but it has been ignored many times.

    Lets work together and make this a forum to be really proud of! We all know the score, we all know the rules so come on, lets play nice!

    Cheers
    Rich.
    #23
  25. curbdawg
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    curbdawg New Member

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    [Sep 16, 2005]
    ???? What just happened

    Why are the moderators so heated.
    I just got a lot of info from this forum.
    #24
  26. marctwo
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    marctwo Member

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    [Sep 16, 2005]
    [ QUOTE ]
    6. A 'Diverter Valve' exhausts to the inlet side of the turbo, which is open to the atmosphere, so the best it can do is equalise the pressure across the inlet turbine
    7. A 'Dump Valve' exhausts to atmosphere, meaning that the best it can do is equalise the pressure across the inlet turbine.

    [/ QUOTE ]

    First of all I'd like to state, for the record, that I know absolutely *nothing* about think kind of stuff, although I'd like to learn. Please put me right if I am totally out on this one.

    Just because in both (6) and (7) the pressure is the same on both sides of the turbine, it doesn't mean that this 'equalised' pressure is the same in both (6) and (7) does it? In other words, whilst a diverter valve may also equalise the pressure, surely this equalised pressure will be higher than that in the dump valve system? Does that count for anything?
    #25
  27. RichA3Turbo
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    RichA3Turbo ...Watching you! Staff Member Moderator

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    [Sep 16, 2005]
    [ QUOTE ]
    [ QUOTE ]
    6. A 'Diverter Valve' exhausts to the inlet side of the turbo, which is open to the atmosphere, so the best it can do is equalise the pressure across the inlet turbine
    7. A 'Dump Valve' exhausts to atmosphere, meaning that the best it can do is equalise the pressure across the inlet turbine.

    [/ QUOTE ]

    First of all I'd like to state, for the record, that I know absolutely *nothing* about think kind of stuff, although I'd like to learn. Please put me right if I am totally out on this one.

    Just because in both (6) and (7) the pressure is the same on both sides of the turbine, it doesn't mean that this 'equalised' pressure is the same in both (6) and (7) does it? In other words, whilst a diverter valve may also equalise the pressure, surely this equalised pressure will be higher than that in the dump valve system? Does that count for anything?

    [/ QUOTE ]

    You got it spot on there. a dump valve will drop the pressure a DV will equalise

    Rich
    #26
  28. dcallaghan
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    dcallaghan Member

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    [Oct 4, 2005]
    [ QUOTE ]
    First of all I'd like to state, for the record, that I know absolutely *nothing* about think kind of stuff, although I'd like to learn. Please put me right if I am totally out on this one.

    Just because in both (6) and (7) the pressure is the same on both sides of the turbine, it doesn't mean that this 'equalised' pressure is the same in both (6) and (7) does it? In other words, whilst a diverter valve may also equalise the pressure, surely this equalised pressure will be higher than that in the dump valve system? Does that count for anything?

    [/ QUOTE ]

    The air inlet side of the turbine is connected to atmosphere, meaning an equalised pressure can only be the same as the atmosphere.

    I struggled to think of a good analogy - I will post one later.
    #27
  29. marctwo
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    marctwo Member

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    [Oct 4, 2005]
    Ah, I thought that might be the case. I'll leave it to people who know what they are talking about next time ! /ubbthreads/images/graemlins/tongue.gif
    #28
  30. RevoKev
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    RevoKev in the fast lane

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    [Oct 5, 2005]
    #29

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