dump valves
- Thread starter williams
- Start date
It's not quite as simple as how pretty they sound, but I'll grant you that this is all most people seem to be interested in.
I'd consider going back to a recirculating one (albeit uprated) because I like the idea of putting the charge back in before the turbo... and I like the idea of my car not sounding like it sneezes every time I lift-off.
I like the idea behind the SQV/SSQV style unit; they use boost to hold them closed and only open when there's vacuum behind the throttles, but whether they're really any better I don't know.
I'd consider going back to a recirculating one (albeit uprated) because I like the idea of putting the charge back in before the turbo... and I like the idea of my car not sounding like it sneezes every time I lift-off.
I like the idea behind the SQV/SSQV style unit; they use boost to hold them closed and only open when there's vacuum behind the throttles, but whether they're really any better I don't know.
I'm going to take a punt here on a stronger spring so it seals better at higher boost; plus if you've got an air-filter relocation pipe or and after-market alloy pipe on the turbo, there's probably nowhere to plumb it into.
I'm happy to be told that I'm wrong and have fallen for some common myth, if that's not the case.
I'm happy to be told that I'm wrong and have fallen for some common myth, if that's not the case.
darkyGTI-R
New Member
Go with what ever you like mate people say there are pros and cons at the end of the day it's your car do what you will
gtir_pimp
New Member
darkyGTI-R
New Member
It does sound good though if you like showing off when boosting off lol not that I ever do;-)
I've heard it quoted before that running no BOV does not significantly reduce the life of your turbo - the key word there is significant; statistically you can't tell that a turbo has failed earlier than it would have if you had the BOV.
Logic dictates that spinning the turbo backwards or stalling it when the throttles are closed, is a bad thing... but apparently it doesn't do as much damage as people think. - I can't remember where I got that from, so I'm happy for people to tell me otherwise.
Logic dictates that spinning the turbo backwards or stalling it when the throttles are closed, is a bad thing... but apparently it doesn't do as much damage as people think. - I can't remember where I got that from, so I'm happy for people to tell me otherwise.
On the duarbility issue of not running a DV. Standard bearings are not as strong as uprated bearings. However if we were worried about durability we would all be running at 0.7Bar and there aren't many people who are. I know of people who have run on a standard turbo without a DV and had no problems. I know of people who run a DV and have had their turbo fail. Does running without a DV make a turbo fail? Its just another factor in driving a 19 year old car.
Personally I don't run a DV as the engine responds marginally better without it.
A common mistake people make is they think the "turbo" stalls or goes back wards. It doesn't, its the air that's stopped moving forwards, the compressor will continue to spin. As the throttle is closed the air has no where to go so stops moving forward, stalls and starts leaking out wherever it can. Some will go back over the blades which makes a fluttering noise.
Pressure in the intake system drops but it does so more slowly than when using a DV where the pressure is released quickly. Between a half second gear change you can see my intake pressure drop from 1.9Bar to about 0.8bar before climbing back to 1.9Bar when the throttle re-opens. With a DV it drops to 0bar in tenths of a second. My turbo is quite responsive and my intercooler pipework is minimal so the difference is tenths of seconds between no DV and a DV. IIRC you run 1 bar and a TMIC so you might find it all marginal as well. If you had a huge intercooler, long pipe run and a DV you might find a more significant difference in lag. Best solution then is not to run a large intercooler and have a huge pipe run rather than worrying what your DV is doing ;-)
Now think what your recirc DV is doing, is it really "feeding air" back into the turbo? If the high pressure air is moving to atmospheric pressure between the air filter and the compressor, the higher pressure air after the compressor will also want to go past the compressor blades to the lower pressure area. If you consider my setup with no DV loses about 1Bar of pressure between gear changes, can you imagine the re-circed air is going to make any difference to the amount of air pouring past the compressor wheel? Whether you use a DV, recirc or nothing, it will all get down to atmospheric pressure sooner or later.
George, I've got my old DV you can have if you want. It goes "ppsssh"
I'm not sure how desirable the noise is? You can swap over and see if it makes any difference to the response or noise.Buy me a coffee at the next meet or a burger if you're feeling flush ;-)
Well a burger is £6 but I will let mine go for a coffee which is about £1.50. Maybe George could have yours for a Sunday roast and half a bottle of whisky?
I don't need a SSQV, I've got an SQV - I think that's the same as Andy isn't it?
I've also got a spare Bailey DV24 (the single piston one that leaks at idle and causes the revs to go up).
I can always use more for my collection, and I think the resale value on an SSQV is more than the cost of a burger... maybe I should buy you the burger and the coffee!
I could also blank my BOV fitting though... then maybe I wouldn't get so many comments about my car 'sneezing' from the people at work.
I've also got a spare Bailey DV24 (the single piston one that leaks at idle and causes the revs to go up).
I can always use more for my collection, and I think the resale value on an SSQV is more than the cost of a burger... maybe I should buy you the burger and the coffee!
I could also blank my BOV fitting though... then maybe I wouldn't get so many comments about my car 'sneezing' from the people at work.
Just disconnect the feed to the actuator in the DV. It will reamin closed. Quicker than taking out your DV. I ran like that for a while until in the end I just ripped it out and blanked it all off. You can see if you prefer the new sound then ;-)
Trondelond
Active Member
I was thinking about that - just blocking (or removing) the vacuum to the DV will cause it not to open? I suppose that will happen with the SSQV at least, as it closes harder the more pressure you give it.
I've got an odd problem now - I 've been running my SSQV in recirc mode for a while, and figured I'd disconnect the recirc bit. Now it seems to dump both through the air filter and through the DV. However, I'm running a shocking 0.6 bar, would this have an effect?
Vacuum is fine at idle, and I've not registered any leaks.
I've got an odd problem now - I 've been running my SSQV in recirc mode for a while, and figured I'd disconnect the recirc bit. Now it seems to dump both through the air filter and through the DV. However, I'm running a shocking 0.6 bar, would this have an effect?
Vacuum is fine at idle, and I've not registered any leaks.
Trondelond
Active Member
I'm offended.
pulsarmoley
Member
why would you buy a fake dv? :noidea:, in my opinion i dont mind the sound of a dv on a turbo car, but if you want the sound of a dv on a normally aspirated car..... YOU SHOULD BUY A CAR WITH A TURBO! Another chavvy product :wankah: anyone elses opinion?
Demon Tweaks sell them, they're £159.... I think I've said too much! :behindsofa: