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DV Tuning / Set up

Discussion in 'A3/S3 Forum (8L Chassis)' started by g60leigh, Feb 19, 2013.

  1. g60leigh
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    g60leigh Well-Known Member

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    [Feb 19, 2013]
    I have seen all the reference to the different spring rates for the Forge DV's etc.

    But is any one able to explain/clarify to me:

    1) what does the DV do (I.e how does changing it improve performance on the car)

    2) what does increasing the spring resistance do (again how does it help)

    3) other than the obvious Forge 007/8 valves what have others used and their opinions on them. Also when does it become worthwhile fitting one of the larger DV's

    I have a fair idea on the above. But would like some educated opinions to clarify as i would not class myself to be an expert by any stretch of the imagination and also thought it would be useful for noobs.
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  3. 16Klappe
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    16Klappe Princess Clap.

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  4. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Feb 19, 2013]
    1) the dv is essentially a pressure valve designed to relieve the boost pressure in the charge system once airflow is abruptly stopped due to the throttle closing... its main job is to protect the turbo from damage caused by compressor stall... changing it to an aftermarket one can in some cases makes the operation more responsive but for the mos part turns it into a serviceable item that is arguably more reliable at the higher boost pressures seen after tuning... the valve should not leak under pressure as this is essentially a boost leak...

    2) it doesn't... the springs job is simply a return spring... its not to hold the valve shut as there is pressure equalisation between the inside of the piston (feed in the top of the DV) and the DV's body... this is enough to hold it shut... stiffer the spring, the more vacuum is required to crack the valve open which in turn makes it less responsive and makes the surface area of the opening to release pressure smaller... this means the pressure takes longer to drop potentially leading to compressor stall and eventually damage to the turbo... generally speaking there is no requirement to use anything other than a green spring in a Forge 007/008 for example

    3) Forge gear is good quality and they supply service kits that are cheap to buy... they have been blighted recently with potential for leaking but the new versions of the valves have addressed this and are fine... only reason to go for a bigger valve such as the Forge super size I am running is when you have increased potential for volume of air in the charge system such as when fitting a bigger turbo (350hp is a ball park figure) then you would benefit from running a larger valve...

    <tuffty/>
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  5. g60leigh
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    g60leigh Well-Known Member

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    [Feb 19, 2013]
    Thank you 16Klappe & Tuffty.

    That's a great service guide I read a little while ago.
    And Tuffty that's a perfect explanation.

    That's how I understood them to work. But was wondering if I was missing something with all of the different options available. If there was a benefit to performance by changing out.

    I have a Forge 008 with green spring installed. But also have an adjustable DV in the garage and didn't know if it was worth fitting now I have had my map upgraded.

    I wasn't sure if I would leak boost if the spring was not strong enough.
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  6. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Feb 19, 2013]
    Stick to the 008.. a DV has no bearing on what the maps does... just the resultant power if its leaking or otherwise faulty or not designed to be run on a 20v with std management... such as atmos valves or 50/50 ones like the Split-R... std management requires a diverter valve... end!....

    <tuffty/>
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