"Whoosh..." Dump Valves - Which One?
10 May 2002, 05:22 PM
#1
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Just got an MY99 and would like to find out what the best option is to go for a Dump Valve.
Would fitting an aftermarket one invalidate my 3 year manufacturer warranty?
What differences can I expect with the car except for the audible increase in noise between gear changes?
I'm new to all of this so I'm sorry if the question has already been done to death.
Many Thanks
Would fitting an aftermarket one invalidate my 3 year manufacturer warranty?
What differences can I expect with the car except for the audible increase in noise between gear changes?
I'm new to all of this so I'm sorry if the question has already been done to death.
Many Thanks
10 May 2002, 06:05 PM
#3
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Thanks for that m8.
Been to the Bailey website and checked em out. Can I assume a DV26 is what I am looking at for an MY99 standard UK model. Will I need to order the fitment kit as well?
Will I see any acceleration improvements?
One last question.
Had my motor into the dealership recently cos the tickover was all over the place. They replaced the Air Flow meter under warranty for free and that sorted it.
Don't suppose fitting a Bailey Dump valve will affect the setup do you?
Sorry for my lack of technical nous on the subject.
Cheers.
Been to the Bailey website and checked em out. Can I assume a DV26 is what I am looking at for an MY99 standard UK model. Will I need to order the fitment kit as well?
Will I see any acceleration improvements?
One last question.
Had my motor into the dealership recently cos the tickover was all over the place. They replaced the Air Flow meter under warranty for free and that sorted it.
Don't suppose fitting a Bailey Dump valve will affect the setup do you?
Sorry for my lack of technical nous on the subject.
Cheers.
10 May 2002, 06:21 PM
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10 May 2002, 10:30 PM
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All the DV does is make a nice whoooosh noise no difference on acceleration, dont forget you already have a DV fitted but a recirulating one(no whooosh)
i would recommend to buy a fitting kit for EVO DV.
i would recommend to buy a fitting kit for EVO DV.
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11 May 2002, 09:42 PM
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Two rolling road results for you to consider, one car run on two dates with and without risirc dump valve (the only change i am aware of):-
Atmos = 232bhp
Resirc = 260bhp
Can't remember the torque figures
Don't know why, again to my knowledge both valves were in good working order, is that the reason subaru fit resirc??
Atmos = 232bhp
Resirc = 260bhp
Can't remember the torque figures
Don't know why, again to my knowledge both valves were in good working order, is that the reason subaru fit resirc??
12 May 2002, 09:24 AM
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planky, thats not just what a DV does, the idea is that it releases the pressure in the intake so when you chane gear it allows the turbo to spin under no pressure, so when you put your foot back down, the turbo will spool back up a lot faster, hence you cold say that it would improve acceleration.
In my opinion the best option if you want a stable idle and a bit of a woosh would be to go for a re-circ and an induction kit, (not an oil based filter like HKS, as they will eventualy fould up you MAF, and Subaru charge 230 for a new one)
In my opinion the best option if you want a stable idle and a bit of a woosh would be to go for a re-circ and an induction kit, (not an oil based filter like HKS, as they will eventualy fould up you MAF, and Subaru charge 230 for a new one)
14 May 2002, 04:53 PM
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MAF = Mass Air Flow, and as the HKS Cone uses oil to filter it can and does end up killing you MAF Sensor, that said I have one on mine as it came with the car, havent replaced it, but probably will
15 May 2002, 04:44 PM
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panel filter should be ok as this is what i had fitted by TSL and they should know. They took my cone off slapped me to my senses then robbed me for a few quid. But hey at least the MAF is gonna be ok phhhheeeeeeeeeeewwwwwwwwwwwwwww!!!
j
j
15 May 2002, 04:50 PM
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DMB :
Atmos = 232bhp
Resirc = 260bhp
You actually believe a resirc gives you 28bhp!!! If they did everyone would be buying them
Think you'll find only modest gains (if any) can be got from a DV
Its a sound thing - and only really important for very highly tuned turbo cars.
Jza
Atmos = 232bhp
Resirc = 260bhp
You actually believe a resirc gives you 28bhp!!! If they did everyone would be buying them
Think you'll find only modest gains (if any) can be got from a DV
Its a sound thing - and only really important for very highly tuned turbo cars.
Jza
17 May 2002, 08:16 AM
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Hi all,
As said earlier dump valves will not (in theory) show a higher BHP on rolling roads BUT they do something for performance... why else do all rally teams use them.
Someone said earlier they allow the turbo to spool up quicker and this is for sure. Early WRX etc were fairly slow spooling and a good quality DV will give you a noticeable difference. It will seem MUCH more responsive on pick-up through the gears. I used to use the APEX twin chamber with fine tune diaphragm. Pricey but very good with adjustable exhaust apertures to reduce or increase noise depending on your preference.
You must be careful because cheap i.e. Bailey types do not idle well on off the throttle hence twin chamber. This is something to do with releasing low and high pressure on the same diaphragm... always a compromise.
Laters all,
As said earlier dump valves will not (in theory) show a higher BHP on rolling roads BUT they do something for performance... why else do all rally teams use them.
Someone said earlier they allow the turbo to spool up quicker and this is for sure. Early WRX etc were fairly slow spooling and a good quality DV will give you a noticeable difference. It will seem MUCH more responsive on pick-up through the gears. I used to use the APEX twin chamber with fine tune diaphragm. Pricey but very good with adjustable exhaust apertures to reduce or increase noise depending on your preference.
You must be careful because cheap i.e. Bailey types do not idle well on off the throttle hence twin chamber. This is something to do with releasing low and high pressure on the same diaphragm... always a compromise.
Laters all,
17 May 2002, 10:31 AM
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Having fitted the Scoobysport Forge DV Atmos to my MY99 I think it has made a difference. Maybe not to power (outright bhp) but on WOT and changing gear it picks up again much quicker, and hence making the car a little faster, than with the recirc - this would also seem to support what has been written above about less spool up time.....
17 May 2002, 04:28 PM
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OK then, the concensus seems to be that you get what you pay for!
How much would the Scoobysport Forge DV Atmos cost me as opposed to the Bailey which seems to be the cheapest option?
The last thing I want is to buy a DV, then find I've got a problem with idle/tickover as I've only just had the Air Flow Meter replaced under warranty to sort that particular problem out!
The dealer I initially took it to reset the ECU after a check engine light came on. After driving away the problem became worse and I ended up going elsewhere to have it sorted out and the AFM replaced which solved the problem.
So really I'm in 2 minds about saving up for a load of goodies once the manufacturers warranty expires in September, then I would have enough cash to pay for a Superchip, Modified Exhaust and whatever else to push things towards the 250BHp mark.
Might just start with a major overhaul of the brakes first then start on my mission to modification!
How much would the Scoobysport Forge DV Atmos cost me as opposed to the Bailey which seems to be the cheapest option?
The last thing I want is to buy a DV, then find I've got a problem with idle/tickover as I've only just had the Air Flow Meter replaced under warranty to sort that particular problem out!
The dealer I initially took it to reset the ECU after a check engine light came on. After driving away the problem became worse and I ended up going elsewhere to have it sorted out and the AFM replaced which solved the problem.
So really I'm in 2 minds about saving up for a load of goodies once the manufacturers warranty expires in September, then I would have enough cash to pay for a Superchip, Modified Exhaust and whatever else to push things towards the 250BHp mark.
Might just start with a major overhaul of the brakes first then start on my mission to modification!
17 May 2002, 04:41 PM
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Forge is 120 + the dreaded from ScoobySport.
Avoid the Superchip
You will be far better off getting the Tek2 EcuTek upgrade utilising the existing ECU which gives on most cars around 270bhp/260lb ft and costs 500 quid or 625 + the dreaded from Power Engineering 
from ScoobySport.Avoid the Superchip
You will be far better off getting the Tek2 EcuTek upgrade utilising the existing ECU which gives on most cars around 270bhp/260lb ft and costs 500 quid or 625 + the dreaded from Power Engineering
17 May 2002, 05:00 PM
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Forge would certainly seem the one to go for. What's the main difference between fitting a Red and a Blue spring which I picked up on from a previous thread?
Would fitting this type of DV definately not cause any problems with the idle/tickover setup, as I want to avoid that problem altogether as it pi$$es me off no end having the tacho bouncing about all over the place!
Why would you avoid Superchipping a Scooby?
I had one fitted to my old MK3 Golf GTi without any problem except it still felt like a tortoise when overtaking.
Thanks for the advice though.
Would fitting this type of DV definately not cause any problems with the idle/tickover setup, as I want to avoid that problem altogether as it pi$$es me off no end having the tacho bouncing about all over the place!
Why would you avoid Superchipping a Scooby?
I had one fitted to my old MK3 Golf GTi without any problem except it still felt like a tortoise when overtaking.
Thanks for the advice though.
17 May 2002, 05:11 PM
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Not sure on the spring??? Mine and a mate have the forge and have had no idling probs whatsoever.
Superchips are widly regarded as "a bad thing" TM on a scoob. NA cars are a different kettle of fish like your Golf. The Superchip ups the boost with a bleed, and places a fuel cut defender in and removes the fuel cut altogether - not a good idea. If you want to raise boost safely a Dawes will do just as good (see Drivetrain section - loads of info) and it costs 35 quid, or the TEK2 upgrade I mentioned.
Hope that helps!!
Superchips are widly regarded as "a bad thing" TM on a scoob. NA cars are a different kettle of fish like your Golf. The Superchip ups the boost with a bleed, and places a fuel cut defender in and removes the fuel cut altogether - not a good idea. If you want to raise boost safely a Dawes will do just as good (see Drivetrain section - loads of info) and it costs 35 quid, or the TEK2 upgrade I mentioned.
Hope that helps!!
17 May 2002, 05:26 PM
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The EVO DV is perfect for a scooby,it was originally designed for cars that cant run normal DVs (rs turbo,scoobys etc) ive got a couple of mates who run EVO DV on scoobys and both cars run perfect
17 May 2002, 06:10 PM
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To continue re: Idle
When I said a cheap DV will cause idle problems I should have explained a little more as follows -
The idle will be ok until you throttle and release i.e. in slow standing traffic or if you were at a stand still and you revved the engine. Then upon release the single diaphragm would stroke too far and in worst cases cause a stall.
Hope this helps,
Julian
When I said a cheap DV will cause idle problems I should have explained a little more as follows -
The idle will be ok until you throttle and release i.e. in slow standing traffic or if you were at a stand still and you revved the engine. Then upon release the single diaphragm would stroke too far and in worst cases cause a stall.
Hope this helps,
Julian
17 May 2002, 08:07 PM
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Wish a few others thought about it that way - make it STOP better before making it GO better ... you know it makes sense
edited to say i only read as far as the "might uprate the brakes first" post...
[Edited by RaZe-=Buzz=- - 5/17/2002 8:09:13 PM]
edited to say i only read as far as the "might uprate the brakes first" post...
[Edited by RaZe-=Buzz=- - 5/17/2002 8:09:13 PM]
17 May 2002, 10:31 PM
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A dump valve cannot give more BHP... It only releases compressed air on lift off as it has nowhere to go, during acceleration, both recirc & VTA DVs are closed... Anyone care to explain how a DV might give an increase in power when it's not actually doing anything when accelerating?!?!
Also, i don't seem to understand why a VTA DV would would trick the ECU into thinking that more air is being flowed than when using a recirc. Surely it would be the other way round, after all the air flow meter would read the recirculated air twice! Also doesn't the level of boost in the maifold have something to do with it? This would be negative so only minimal fuel would be fed into the engine no matter which DV you are using.
I'm prepared to be shot down in flames but no-one seems to have ever offered a conclusive explaination to this.
Flame suit on.
Sorry if this is the wrong thread, seemed appropriate at the time....
Also, i don't seem to understand why a VTA DV would would trick the ECU into thinking that more air is being flowed than when using a recirc. Surely it would be the other way round, after all the air flow meter would read the recirculated air twice! Also doesn't the level of boost in the maifold have something to do with it? This would be negative so only minimal fuel would be fed into the engine no matter which DV you are using.
I'm prepared to be shot down in flames but no-one seems to have ever offered a conclusive explaination to this.
Flame suit on.
Sorry if this is the wrong thread, seemed appropriate at the time....
17 May 2002, 11:46 PM
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Cool!!! Flame suit on.
Nice comment, seems there is a lot of ****e about DV/bOV's here, at the end of the day they have on as standard, if it doesn't screw the idle and makes a cool sound between changes, who gives a *****
beer...... hence the inglish
Nice comment, seems there is a lot of ****e about DV/bOV's here, at the end of the day they have on as standard, if it doesn't screw the idle and makes a cool sound between changes, who gives a *****
beer...... hence the inglish
18 May 2002, 05:49 AM
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Hello
To Ricco :
The air is metered by the MAF, just after the aibox.
With a recirc DV, it is routed in the pipe,just before the turbo inlet. It's not going twice to the MAF.
With a VTA, fuel is still injected in the motor, but less less air, so you're running rich, but for how tenth of second ?
Sometimes, when the fuel can not burn inside the motor, it passes through the exhaust, vaporised and burn when it meets air !
Just my 0.02 €
Cheers.
To Ricco :
The air is metered by the MAF, just after the aibox.
With a recirc DV, it is routed in the pipe,just before the turbo inlet. It's not going twice to the MAF.
With a VTA, fuel is still injected in the motor, but less less air, so you're running rich, but for how tenth of second ?
Sometimes, when the fuel can not burn inside the motor, it passes through the exhaust, vaporised and burn when it meets air !
Just my 0.02 €
Cheers.