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Which dump valve would you guys choose.

Hello again,

I know that a recirculating dump valve would proberly be better for the car. But the dump valves that dump to atmosphere sound so cool , I know im a kid at heart Any off you guys know of good dump valves?. Or if you really dislike atmosphere dump valves could you list or recommend a dump valve that recirculates back into the induction system.



Btw Forgive me for spelling mistake, cant be bothered to run spell checker

Get the wastegate flutter. My mates Cossie has that and its mint.

After that I like the sound of Jap cars, the short high pitched "Pish", but that is a blow off valve rather than a dump valve..

The dump valve releases the pressure from the system to stop the turbo stalling so Im lead to believe. Hold on, Ill get a proper explanation....

Here it is, typed faster than the speed of light (or copied and pasted, lol!)

Right, at the very simplest level, engines create power by exploding petrol, in order to do this they need air.

The amount of air that an engine can consume is limited by many factors, including the cam, the breathing limit of the head, the size of the valves and the size of the engine itself.
One way to overcome all these limits in one go is to go for forced induction, this is the general term for any device that rams air into the engien at more than atmospheric pressure, ie turbos or superchargers.

The way a turbo works is that it basically has two big fans in it, which are mechanically attached to each other, so that when one spins, the other spins as well.

The exhaust gasses from the engine pass throguh one fan, making it spin, this in turn spins the other fan, the other fan is in the inlet path for the air coming into the engine, so it bascially blows a whole load of air at the engine under high pressure, thus allowing it to get more air in (and hence burn more fuel)

Now there is a problem here, when you back off the throttle to change gear you close the intake path more or less completely, this means that the turbo has nowhere to push the air to, so it makes it stall, this is bad for a couple of reasons, firstly it means it has to spin up again, which means a temporary loss of boost when you get back on the throttle and secondly it means that there is perssure on the turbo itself, cause one fan is trying to stop while the other still wants to keep spinning, this can shorten the life of the turbo.

Now what a dump valve does is detect the difference in pressure when you shut the throttle and basically open a valve (i.e makes a hole) that the pressure can escape through to stop it bouncing back at the turbo and stalling it, this vent of gas is the noise that you hear.

Most production cars (even the metro turbo!) have a dump valve fitted as standard, but they are silent operating (more or less if you really listen you can hear them sometimes).

On hugely powerful rally cars and stuff the turbos are running so mcuh boost that the standard valve cant cope, so they install these loud after market ones instead, on a lightly modified car though you will see no benefit from one, hence my opinion of them as tacky, its making a load of noise trying to make let everyone know you have a turbo, bit like having turbo written up your car or whatever, i personally prefer things to be kept a secret, people can find out when they race me instead!

Thats only a VERY brief explanation and there is a lot of detail missing, but hopefully its enough to help you understand the principle of dump valves, and even a little bit about turbos as well.
  Williams 2, STi N12

Why not fit an ALS system? Then you can have some real popping and banging!! Probably destroy your manifold though.
  172 Cup

"but that is a blow off valve rather than a dump valve.."

Same thing just different names!

How come they make a different noise?

ALS is the daddy, but expect engine rebuils more often than you eat tea!

As i was told by an expert, why would you want fuel exploding in your turbo?
now how long do you want your turbo to last? ie 1000 miles? (if lucky!)
Chu, what car is the DV for to start with? and what is fitted to it at the moment?
If the car was designed with a re circ then IMHO id stick to that, if you have serious lag still with a recirc then id go for a DTA but you may get problems with it.....

  172 Cup

"Most production cars (even the metro turbo!) have a dump valve fitted as standard, but they are silent operating (more or less if you really listen you can hear them sometimes"

Most OE fitted dump valves are quiet because they are the DV30 type (recirculating) not because they are less powerful cars. Manufacturers such as Fiat and Saab fit these as OE and most are made by Bosch from cheap plastic which has a tendancy to split as the years go by. This is when you will be able to hear them.

"On hugely powerful rally cars and stuff the turbos are running so mcuh boost that the standard valve cant cope, so they install these loud after market ones instead"

Again not down to the huge amount of boost but different types of DVs. As rally cars will be running AL systems they have no need to recirculate the boost pressure into the system and use DV26 (atmospheric valves instead).

It also incorrect to say that the standard valve cant cope and thats the reason they are replaced. Old Sierra cossies used to run 7psi as standard, my Punto GT ran 1.6 bar or circa 23psi as standard and the plastic Bosch valve lasted for some time!

TB1 it will be for a Turbo Clio 172. Its been in a few topics on the forums of late Now I have no idea what the standard Turbo Clio 172 runs, cause there isnt a factory one. But on the kit atm there isnt a standard dump valve of any sort. Recirculating dump valve would require a bit more work than just sticking the atmosphere one.

  BMW 320d Sport

Recirculating is the way to go. Atmospheric sounds like the number 27 bus opening its doors to pick up passengers.

Dont know if Im right on this but isnt the recirculating type or the use of no dump valve at all, the thing that causes the twittering on overrun that you hear on the WRC cars? Ive never heard a WRC car chuff with an atmospheric valve...

Anti-lag is pretty good if you wanna keep the turbo spinning between changes. But only if you dont mind regular rebuilds though and have a steady supply of manifolds.

Ive got a plan for genuine flames from my Clio anyway and it doesnt involve a spark plug welded into the exhaust or over-fuelling of any kind, or a stone age carb conversion. Well see if it works once I have it hooked up tomorrow. The manifold should be able to take it I reckon.
  7.6cc :D

The forum queen of tacky has something to say:-

Voooooooooom tiisssssssssssshhhhhhhh voooooooooooom tissssssssshhhhhh!!!!!!

Get a noisy one, they are wicked!
  clio williams, Ph1 172

Its not a dump valve you can here on standard turbo cars its the wastegate you can here. If I were you mate id get an atmospheric dump valve but get a decent one and have a good diaphragm in it. I think they make them out of kevlar. They need replacing quite often. If you cant be arsed with that get a Piston dump valve, like what Bailey make. they are pretty good i think but cost more.
  Corsa 1.3 CDTI

Yerr get a really noisy one so you can show everyone you have a big ol turbo slapped on your car and people in Cossies will quiver at that sound cause it will munch their little cars up and spit them out.

Hi Guys, Sorry for the dealy, I had to go to MK of all places for an EDS Meeting.. ...

Re the dump vavle, the plan is to have the throttlebody downstream of the boost as opposed to upstream.

SO, yes, it will need one..

as for type.. one that works ! lol..

will look at some specs n let ya know.


Twin atmospheric dump valves are a must, why do you think I want to slap a turbo on my 16v, mate has got one on his 5 really loud, turns more heads than bass or an exhaust
  Clio 182, OctaviaVRS

Ive got a K-Tec twin dump valve setup on my car, and they do sound superb - its not annoying in anyway, and the more boost i run the louder they are between gear changes, or just letting off the throttle......

Just go for a recirc valve youll have no probs, as someone mentioned the standard bosch plastic valves as fitted to Ford, Fiat, Audi, saab etc. do break down over time.

These guys build quality kit

I have the DV 006 valve on my Coupe, good response, no boost leak yet after a year and a half and is rebuildable anyway so you can change springs/diaphrams etc. mine cost me £70 but I picked it up direct from them, mail order its about £90, a quality product I would recommend it.

As for the whole pishtt sound, you will still hear it with a recirc valve especially with and induction kit it just wont be so Max power

  Mrs' valver! &myV6 veccy

A lad i know has a big Lancia Dedra 2.0T running about 243bhp so the printout said, and he opted for the recirculating valve.

As Sandys said you can still hear it, but the sound is not as in your face as the atmospheric, and in my opinion just sounds so much smoother and nicer.