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  • dump valve

    any one know where i can get a dumpvalve for my vxr

  • #2
    dump valve £105 lmf pipe for valve to fit in to £60 courtnay

    www.courtenaysport.co.uk/ For all your tuning needs

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    • #3
      I've jsut asked about this. Thorney seem to say it can loose power on the VXR so best to stear clear.

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      • #4
        Dump Valve installation

        Our hose with the dump valve spigot is £57.95 and the D Valve with a minor fitting kit £85.00. http://www.courtenaysport.co.uk/default.htm?page=118
        As regards suitability for VXR and losing power... the only way a dump valve will make an engine lose power is if the dump valve leaks, for this to happen there are 2 causes. The first is that the valve is faulty the second and by far the most common cause is that it has been fitted incorretly. This problem goes right back to the early days of the ZLET engine in the Astra Coupe however it still applies to Z20LEL, Z20LER and of coarse Z20LEH (VXR)
        80% of cars we see in the workshop have the dump valve fitted incorrectly, even by tuners. This is down to the trigger pipe source.... unfortunatly the easiest place to pick up this source is in fact the wrong point hence the extent of the problem.
        I have cut and pasted in the relevant details from our web site giving a full explanation...
        Dump Valve Fitting Recommendations
        This is a guide for fitting a dump valve and eliminating dump valve related drivability issues on Astra G and H, Zafira A and B and VX220 fitted with the Z20LET - LEL – LER - LEH engines.
        The dump valve for these engines must be a twin piston unit as the car has air mass metering. The twin piston unit stops the valve breathing un-metered air on vacuum, confusing the engine ECU.
        How a Dump Valve Works
        Traditionally a dump is fitted in the boost pipe close the inlet manifold; it has a vacuum - boost trigger pipe taken from the inlet manifold between the throttle body and the engine. When driving the car hard on boost there is boost pressure pushing on the dump valve, however there is equal boost pressure pushing on the dump valve diaphragm on the other side. This holds the dump valve shut in equilibrium. When you lift off the throttle the throttle body closes this creates a vacuum in the manifold thus in the boost – trigger pipe, this vacuum pulls on the dump valve diaphragm and with the boost pressure in the inlet pipe pushes the valve open releasing the air into the engine bay with a whoosh.
        How is this Vauxhall Engine Different ?
        These engines work as above, with one major difference. The boost - vacuum trigger pipe is run through a vacuum storage capsule, and a solenoid that is triggered by the engine ECU. There are switches on the pedals so the ECU knows when you de-clutch and trips the solenoid to create the vacuum quicker to the original equipment recirculation dump valve built into the side of the turbo.
        This vacuum solenoid arrangement is also used on part throttle to regulate the air mass to the engine, i.e. when the turbo is trying to make boost due to its small size but the load demands and throttle angle do not require boost, it opens and shuts the factory re-circ valve to regulate boost improving drivability, kind of like a secondary throttle.
        This is the source of the trouble. If you use this trigger source (i.e. from the original vacuum storage) for the aftermarket dump valve it will pulse the new valve on part throttle, the previously metered air is then released into the engine bay and will cause driveability issues on the fuelling. In some circumstances the car will also go lean, in this situation the TC (traction control) light can come on.
        The Fix
        The cure is to give the aftermarket dump valve its signal from a true non interrupted vacuum source; we recommend the fuel pressure regulator. For further improved driveability, it is possible to leave the original equipment valve still working so the engine management can regulate, control and pulse this valve. However the aftermarket valve will operate slightly quieter.
        I hope this helps and clears up any confusion.
        sigpic
        29 Years as Vauxhall Tuners

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        • #5
          Interesting reply that.
          So basically you want the DV as close as possible to the top hat?
          May get one for the missis as a present

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          • #6
            Originally posted by Daimo
            Interesting reply that.
            So basically you want the DV as close as possible to the top hat?
            May get one for the missis as a present
            Yes that is also a good idea, but the main point is to insure that the trigger pipe (small vacum /boost pipe is joined in to the vacum pipe at the fuel pressure regulator.
            sigpic
            29 Years as Vauxhall Tuners

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            • #7
              And performance gains?
              We've not seen any, on any car, ever. If its sold as a noise 'enahancement' then great but personally I wouldn't recommend them if its a performance gain you're after.
              The potential downsides (even from poor fitting) up to and including causing the car to run lean mean we won't fit them to zlets - period.

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              • #8
                i have one
                i stick my head out the window and sneaze
                pppppppppppppppsssssssssssssssssssssssssssssssssss ssssssssssssssssssssssschhhhhhhhhhhhoooooooooooooo ooooooooooooooooooooooooooooooooooooo
                thats with sports mode on

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                • #9
                  I have one fitted as per the above instructions mine is the trumpet one, it works fine, the main reason i fitted this is the inlet temp, after every dump the engine draws in a new cold air charge, is the inlet temp on the vxr important, im sure ive read this, will you tuners make up your minds??? :mrgreen:

                  www.courtenaysport.co.uk/ For all your tuning needs

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                  • #10
                    Originally posted by Thorney
                    And performance gains?
                    We've not seen any, on any car, ever. If its sold as a noise 'enahancement' then great but personally I wouldn't recommend them if its a performance gain you're after.
                    The potential downsides (even from poor fitting) up to and including causing the car to run lean mean we won't fit them to zlets - period.
                    Your quite right John, no performance gains from these nor do we claim any, it does have the ability to dump more boost due to its size on high boosting engines however this does not increase bhp. Its main attribute is noise, as stated earlier they will cause a lean mixture on cruise if they are fitted to the wrong trigger source. and can even bring on the EML for random cylinder miss fire, also on ZLET's the TC can come on as a result ! This is why it is important to use the vacuum boost at the fuel pressure regulator. If you use this vacuum point the Dump valve is in equilibrium and will not open (unless faulty) This whole confusion was started back in 2002 due to the original printed instructions being wrong, Bailey have since re- written their instructions (about 6 months ago ) which now mirror ours. As said in my last post we are still correcting cars almost daily.
                    As regards drawing in cold air... on lift off the dump valve blows the moment the throttle in closed, as soon as the boost has gone- blown there is vacuum in the manifold and this will immediately close the dump valve, the change over could be measured only in milliseconds if at all so the gain here is negligible if at all. Sorry
                    sigpic
                    29 Years as Vauxhall Tuners

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                    • #11
                      So there you go, we both agree that DV's are about noise and not power, but if you want one make sure its fitted by an expert - does sound like Courtenay know what they're talking about (as usual :P ) so I'd recommend heading over there for one. (We still won't fit them).

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                      • #12
                        pffsssst Dump Valve.
                        Renault 5 GT.
                        name a production vehicle with an 'Acoustically enhancing' dump valve fitted as OE
                        or
                        a Professional Race Car with one added?
                        sigpic

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                        • #13
                          I must admit I would still like one, as I am based in Northern Ireland having courtenay fit it for me is not really an option. So could you tell me if it is easy enough to fit "DIY" do you supply a picture fitting guide or can you recommend any fitters in Northern Ireland who could fit it for me
                          Thanks,

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                          • #14
                            sorry off-topic, but wereabouts u from chris? im in n ireland as well!

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                            • #15
                              its an easy diy fit as long as you no wear the fuel pressure regulator is, if not pop to your vx dealer ask techy to show you. then you need vac pip 18 inc , t-peice same dia and away you go fitted mine about 3 weeks a go all ok.have left the one on the turbo in full working order. :mrgreen:

                              www.courtenaysport.co.uk/ For all your tuning needs

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