View Full Version : dump valves?
dose a dump valve realy help the turbo to last longer or is it just a mith?
TrixNFlix
23-11-2009, 19:09
Oh christ , world war 3 is gonna break out. :eek::scared:
ith a mith ...depends on the application ,boost level and taste .....:D
I was reading through the articles earlyer and came accross this which somes it up quite nicley.
Remember that Renault chose not to fit one as standard on the GT Turbo, yet most manufacturers do fit them as standard equipment (recirculating type) on turbocharged cars. The R5/R11 Turbo has quite a long boost path with reasonably wide hoses, so most pressure waves from the throttle shutting quickly are absorbed in the hoses, so you don't get the turbo damaging effect seen in cars with shorter paths. Hence a lot of people feel there's no need for a dump valve on a R5 GT Turbo or R11 Turbo.
Yea i just presumed he was running a 1.4 not a 1.7, but still good info none the less :scared:
I've run with and without on both the 21 and GTA .Can't say I've noticed any difference on either ..recirc,dump or none .
tonesGTT
23-11-2009, 20:58
dose a dump valve realy help the turbo to last longer or is it just a mith?
No, a dump valve does not really help. It's a myth ;)
What is a Dump Valve?
http://www.grahamgoode.com/pixw.gifMost production turbocharged engines are fitted with a dump valve (http://www.grahamgoode.com/frpua1.htm). This is to vent away excessive turbocharger boost pressure when the throttle is closed.
All Sierra Cosworth and the original large turbo Escort Cosworth models use the same dump valve. The turbocharger fitted to the latest Escort Cosworth has its own integral unit.
The dump valve is the black plastic saucepan shaped object that you will see connected between the intercooler (http://www.grahamgoode.com/frpua2.htm) and the air inlet hose to the turbocharger. You will also see a small hose leading from the top of the valve to the inlet plenim on the engine. Inside the valve is a rubber diaphragm (http://www.grahamgoode.com/frpua1.htm) and a steel spring, with a small insert to support the diaphragm where it seats against the dump valve body.
The dump valve has basically two operating conditions; throttle open, and throttle closed. When the throttle is open, the boost pressure coming into the valve from below the diaphragm is equalled by the pressure onto the top of the diaphragm that comes via the small hose from the engine plenim chamber. As the pressures are equal, the spring holds the diaphragm onto its seat, and prevents the pressure venting away. When the throttle is closed, the pressure coming into the top of the valve is significantly reduced, (often to a vacuum), and the pressure below the diaphram lifts it away from its seat, allowing the excess pressure to vent away. As the throttle is reopened, the pressures again equalise, the spring pushes the diaphragm onto its seat, and the boost pressure cannot vent away.
http://www.grahamgoode.com/pixw.gifWhy do manufacturers fit a dump valve?
It is for a number of reasons. Without a dump valve, when the throttle was closed, the build up of boost pressure would be immense, very similar to closing a quickly flowing water tap. This excess of pressure, (which could be over five times the running boost pressure), would put the components of the system under a great strain. It would try to burst the intercooler and pipework. More significantly, it would put a large strain on the turbocharger itself, firstly stalling the compressor shaft, then trying to force the compressor wheel out of the turbo, against its bearings.
So, the dump valve prevents mechanical damage to the intercooler & turbo pipework, prolongs turbocharger life, and prevents excessive turbo - lag that would be caused by the compressor shaft stalling.
http://www.grahamgoode.com/pixw.gifWhat can go wrong with a dump valve?The only thing that can go wrong with a dump valve is that the diaphragm can become holed. If this happens, it will not seal, and the boost pressure leaks away all of the time. This will cause the turbocharger to work harder to overcome the leak, (turbochargers will work as hard as they have to, to give the required boost), and this will be noticeable to the driver, as a lack of boost response.
http://www.grahamgoode.com/pixw.gif
Plenty of bs in the above paragraph. Total myth that a dumpvalve makes a turbo last longer imo. Less lag with dumpvalve? :laugh:
the bigger the better,go for it!!!!....:D
iv got a audi a3 1.8t and iv tuck it off just woundering if it will cause any damege or not it seems to be better without it
iv got a audi a3 1.8t and iv tuck it off just woundering if it will cause any damege or not it seems to be better without it
dump valve can cause problems with the engine management as there is a loss of system pressure. There are now VAG friendly dump valves that also recirculate the lost pressure keeping the ECU happy.you say it runs ok though?
I actually had some knob jockey call Turbo Dynamics to ask them if his thrust bearing would fail if he removed his dump valve. To be honest, that annoyed me, as I had my opinion thrown back in my face... However, he told me he'd let me know and I never heard back from him. That says alot.
****ing idiot.
redrocket29
24-11-2009, 18:12
iv got 2 dumps on my 5 is it bad they were on when i brought it should i remove 1?
Gonna get a custom boost pipe made up for 6 of the buggers, 3 facing forwards and 3 facing backwards with pink vacuum hosing, should be a record :smokin:
iv got 2 dumps on my 5 is it bad they were on when i brought it should i remove 1?
Bin both of them, they are gay
i'd think if your running anything over 14psi you should consider a dumpvalve, if you dont like the noise you could always go the recirculating route....
as for renault not fitting them as standard id say its due to the turbo being so small, when your cruising down the motor way there a pain in the ass becuase the turbos wind up at such low revs your continuously dumping as you control the throttle!!!! i have a blanker which i fit if im going on a long journey.
Bin both of them, they are gay
:agree:
A dump valve will harm nothing apart from your RTOC credibility rating :agree: Mine is under review as I have a mixed bag of non 5 stuff so 'they' aren't sure what's what :laugh:
rs250nut
24-11-2009, 19:07
Gonna get a custom boost pipe made up for 6 of the buggers, 3 facing forwards and 3 facing backwards with pink vacuum hosing, should be a record :smokin:
Gt tuning used to fit three to some of their cars claiming it aided spool up, charging **** loads of money for what were standard cossie dumpvalves with shiney alloy covers.:jerkoff:
TrixNFlix
24-11-2009, 19:20
Bin both of them, they are gay
Enjoy them for what they are, an amusing noise. Granted this sound can get anoying sometimes, but I bet most members on here have had one at some time!:eek:
Big Steve - Raider
24-11-2009, 19:23
Enjoy them for what they are, an amusing noise. Granted this sound can get anoying sometimes, but I bet most members on here have had one at some time!:eek:
:ashamed:
TrixNFlix
24-11-2009, 19:27
You know I speak the truth:cooter:
Junglist
24-11-2009, 19:29
when your cruising down the motor way there a pain in the ass becuase the turbos wind up at such low revs your continuously dumping as you control the throttle!!!!.
i miss that :D , although now even without a dumpvalve it still makes a loud enough noise with the wastegate flutter/chatter , :)
For folks running a lot of boost and considering one of those stupid forge "group-A" fisher price things, here's s nugat of information for you:
I've seen engines fail when a diaphram has split because the AEI pipe was connected to the same line as the dump valve. The leak in the vac pipe caued the AEI to see less boost, so ignition timing took a climb for the worse. Those things want melting down and making into something usefull.
Nothing possibly can be useful from group A d/v metal.. its scrap ;) :cooter:
But that's just down to plumbing ,not the DV's fault .Keep all computer/sensor signals pure and you should not see any issues ?
i miss that :D , although now even without a dumpvalve it still makes a loud enough noise with the wastegate flutter/chatter , :)
yeah i love that flutter noise, i'd much rather hear that then my dumvalves psthhh.... :)
i had to fit a valve in the end though because my boost gauge is connected to an outlet on the turbo housing and when it fluttered my boost gauge needle did too and hopped back and forth with the flutter, so i realised it wasn't doing my turbo much good :sad2:
Duncan Grier
24-11-2009, 20:29
i miss that :D , although now even without a dumpvalve it still makes a loud enough noise with the wastegate flutter/chatter , :)
Wastegate flutter is a made up word, they dont make a noise.
Some new type engines vag etc can sometime throw up an error without one but the ecu is programmed to have that compressed air going back to the turbo via recirc. Can lead to running leaner for a very brief time during recirc. Do not think it would kill anything but no point removing if designed to run. Vaux LEH use boost solinoids and recirc to bleed boost.
Piston type recirc gets around the diaphram spliting issues
Each to their own ;)
DG
But he's not got a 5 :laugh: I think I already said that :cooter: obsessed some people ......
Wastegate flutter is a made up word, they dont make a noise.
Indeed, for those not in the know, that noise you hear is infact compressor surge :)
Indeed, for those not in the know, that noise you hear is infact compressor surge :)
http://juracid.co.uk/gallery/forum/Vic_Bob_Handbags.jpg
Duncan Grier
24-11-2009, 20:36
But he's not got a 5 :laugh: I think I already said that :cooter: obsessed some people ......
LOL but you never explained it :D
I have had 3 R5's :P but found they drive the wrong wheels :D
Indeed, for those not in the know, that noise you hear is infact compressor surge :)
Which is? :)
LOL but you never explained it :D
I have had 3 R5's :P but found they drive the wrong wheels :D
aiii, wrong, wrong ,all is wrong
The new Bill J
24-11-2009, 20:48
But he's not got a 5 :laugh:
So why post? After all, this is the R5 owners club :cooter: :laugh:
I'm trying to build bridges :coffee:
Feck me! it's like living in Cockermouth
Duncan Grier
24-11-2009, 20:57
So why post? After all, this is the R5 owners club :cooter: :laugh:
How is that evo :D lol
The new Bill J
24-11-2009, 21:04
How is that evo :D lol
It's currently parked next to my R5 :cooter:
Duncan Grier
24-11-2009, 21:05
Good come back :D got half a R5 in the shed in spares - does that count? :)
newbstar*
24-11-2009, 21:16
Good come back :D got half a R5 in the shed in spares - does that count? :)
NO:cooter:
The new Bill J
24-11-2009, 21:18
NO:cooter:
:agree:
Goodbye Grier :cooter:
Penfold aka The Dealer
24-11-2009, 21:21
3 out of 4 of my 5's have run DV's... including the cup car - although now been removed...
Each to there own, i personally like the dumbvalve noise, but love the compressor surge... :D
Really dont see the point in having 2 or 3 dumpvalve's... although helps tuner's profits.
Wow, another dump valve thread.
We're well overdue another Cup mod' thread...
http://www.youtube.com/watch?v=DltYGfeeRUw
hydrotec78
24-11-2009, 21:27
http://www.youtube.com/watch?v=DltYGfeeRUw
http://www.youtube.com/watch?v=4UCZF_UnG10&feature=related
this dif ,,,opps i mean d v is better :laugh:
Penfold aka The Dealer
24-11-2009, 21:38
http://www.youtube.com/watch?v=4UCZF_UnG10&feature=related
this dif ,,,opps i mean d v is better :laugh:
Seriously would love to have a go in that :D
5alldaway
24-11-2009, 21:43
i ran a 5 with and without a dumpvalve on before, the boost pick up was noticably better without the dumpvalve
i run a dumpvalve these days, not bothered how fast the car goes as long as i get to where i need to be
hydrotec78
24-11-2009, 21:44
It dose look a good laugh.
Big Steve - Raider
24-11-2009, 21:44
:sad::sad::sad:
OMG this thread has now officially degenerated into http://www.durbnpoisn.com/images/faces/shiat.gif
:laugh::laugh:
Rob@Backyardracing
24-11-2009, 22:03
I think the Technical discussion section should be closed.... think RTOC has covered everything and anything to do with a GT turbo.... :coffee:
redrocket29
25-11-2009, 08:58
saying all that face it people f***k it just enjoy are 5's some love them some dont but one thing we agree on we love renault 5 gt turbo's????? yes no
No :p
Why have you joined up to the renault 5 gt turbo club then :laugh: we all know this site is all about that car and how to fit dump valves, plus posting of caravan videos and the cup mod.
To meet chicks :agree:
Any luck with that?? :laugh:
Depends how you define luck ...I have had to lower my standards quite a bit mind :coffee:
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