I'm after a recirculating dump valve for my 20vt, I currently have a baileys DV-36, however I want a change
Can anyone recommend me a good well known recirculating DV?
Thanks

Forge DV 006 with a green spring is the best option in my opinion!

Thanks for the reply mate!
Just want to confirm that particular one; it makes the chatter/flutter noise rather than the "tish" noise?
If so where can I purchase one or these?
Thanks mate

Recirc valves are silent, You may get chatter from your filter, If thats the flutter noise you want?

The valves like the Bailey ones are dump to Atmosphere, Recirc valves, are NON Atmospheric.

Chrissy..

You don't want "flutter/chatter" unless you want a dead turbo.

Wastegate chatter echoing from your cone filter is normal, What reason would that kill the turbo Marc?

So many mixed opinions but it's not wastegate chatter as far as I'm aware. It's compressor stall. Ie it's the sound of the the turbo being forced to slow down with the air chopping through the blades hence the fluttering sound you hear. Don't hold me to that but it's what I've read.

Turbos don't like being forced to slow down, it causes more wear.

Wastegate chatter and turbine chatter are two different phenomenons, the latter obviously not being good for the turbo.

Wastegate chatter is caused by excess pressure affecting the spring, and thus the valve.

So would a waste gate chatter be okay? If so, is this similar to a dump vale?
Thanjs

Full recirc valve with a cone air filter, you will hear the flutter noise you're after. I have drove a coupe with the stock plastic recirc valve and an after market cone air filter and when coming off boost you hear the flutter.
Unless you running very a high levels of boost i doubt this will reduce your turbos life; as this is how it comes out of the factory. I hope this helps.

The Forge dump valve will give you a whoosh or tish sound not a flutter! But as mentioned above (I think), a recirculating dump valve will be silent until you expose the dumping noise by drilling the air intake box or by using a cone filter!

I have both on my two coupes (recirculating and external) and to be honest I can't say which I prefer, the external (Bailey DV) seems to be louder and slightly more aggressive in it's dumping sound.

Everyone loves a good aggressive dump, mrc

I have a hks ssqv on mine and that gives more of a chirp noise. I also have a forge recirculating valve and that gave more of a tishh noise through the airfilter and much quietier than the vent to atmosphere.

I agree, ive had 3 today!

I have baileys dv and get a nice loud tish.
But if I lift off from low boost part throttle I get no tish but a flutter through the cone filter.

Best of both worlds unless it's knackered that is.

You can run without a dump valve and get compressor surge if you want that is the loud flutter associated with motorsport cars.

It's a myth it damaging a turbo, you think even cars running high boost it's still not a lot of pressure, the only thing that will damage a turbo is debris getting to the compressor wheel, overheating or poor lubrication where bearings or seals wear down over time or you don't change the oil regularly. But the actual compressor wheel itself is a sturdy piece of kit, and I have yet to see a turbo be damaged due to not running one lol.

But from a manufacturers point of view dump valves are there to remove that noise that can become annoying over time, and aftermarket companies just jump on the band wagon it's another product to sell isn't it loud, quiet whatever you want all a load of cobblers.

Indeed the chattering noise you hear doesn't mean the compressor is stalling. Rather it's the wastegate that opens and closes rappidly, either due to balancing boost pressure around the spring pressure or the way the boost controller works (on/off solenoid like in the blitz).

I also found a video on youtube a while back showing a guy running a coupe 'proving' you don't get boost peaks when you don't run a blow-off valve. For one thing he uses a damped boost gauge (dial type) so any spikes will be filtered, but also it's missing the point because the idea of a bov is not specifically to get rid of boost spikes, but rather to divert surplus air to some place else than where it will otherwise go (back through the air intake) where it will cause less stress (read on).

And indeed - compressor stall will not cause destruction as 'feared' by some (namely instant and fatal), also the way a turbo compresses air and the way inlets and outlets are designed, if air would go back through the turbo then let's not forget that the inertia of the rotating vanes is higher than that of air PLUS that the force is spread quite evenly across eg. the shaft so it's not going to bend it. At max it will compress the layer of oil a bit more, but that shouldn't be a problem it might just decrease the life of the shaft slightly.

Anyway, WHY compressor stall is bad is just because the turbo will need to be spun up again before it can pressurise the inlet. So it increases the turbo lag. That is also why rally cars have an anti-lag system: to keep the turbo spinning even when they come off the throttle. In fact the force put on the vanes / turbo by the anti-lag is way higher than anything else (and they aren't running bov's either, that would defeat the idea of anti-lag).

Talking about this, you will realise that just about everything has an effect on how the system is put under pressure and how the parts 'suffer' (or cope) with the transient situation of coming off throttle: intake length. Intercooler size, weight of compressor and impellor, size of turbo,...

So, compressor stall isn't so much a bad thing that it will destroy your turbo s soon as it pops its head, but the guys doing drag racing will sure tell you a LOT about turbo cars is to prevent this as they will otherwise lose power when shifting gear. The most basic 'solution' is to keep your foot down when shifting, and pray for the fueling, engine, cooling, diff, clutch,... To be able to cope.

That's it Kayjay it depends on the characteristics of how you want your car to perform. I've had a little play myself and the difference is very minimal on a road car, so it basically boils down to what you prefer, it's a nice sound but it would get on my tits after a while.

But I've had mates who run a few high performance jap mobiles and some don't run them purely for the sound and have never experienced a single problem.

But as I say even relatively high boost like 2bar plus is nothing a turbo compressor can't handle it's not a lot of pressure at all, it is once it's been compressed and ignited in the cylinders lol so yeah as you say the hot turbine side and running systems like anti lag really does put an awful amount of abuse on a Turbo.

I work on gas turbine engines and centrifugal compressors are renowned for their resistance to surging air that's one of the benefits of running them over axial flow which are a lot more delicate, but then also gas turbine engines usually experience extremely high pressures were talking 14 BAR plus , it's then when surging becomes a bit catastrophic

I stand greatly corrected and will update my turbo knowledge book haha.

Either way I'd still rather run a recirc/atmos dv as there is noticeably less lag!

You have a turbo knowledge book you lucky git haha

I think Recirc is the best all rounder still anyway plus has it's own nice little sound going on. Atmos or no BOV would get a bit tedious over time just on that day when you fancy a bit of peace and quiet whoosh or birds in a blender sound lol .... Mind you it's also nice to excersise the child within sometimes they are at the end of the day big boys toys for example a flame coming off throttle still puts a ridiculous grin on my face ..... It's a petrol head thing isn't it.

Best thing to do it get a recirc one. Plumb it in as a recirc type to see what it sounds like. Then unplug it off the air intake pipe so its dumping to atmosphere and see what that sounds like (remember to plug the intake return)
I've got a bailey trumpet jobbie on mine and all it is is a recirc one with a fancy take off.

Forge DV =

An excellent piece of kit that works and sounds fine.

Put simply:

No Dump Valve = Used in motor racing. Most series use restrictors and constantly run ALS. The turbos are heavily modified and lifed to a typical rebuild of ~2000km. There is no reason for any type of "dump" valve on a racing car.

ATM Dump Valve = Used for cars without MAF. Dumps the excess boost on overun to atmosphere to give a "woosh" sound, not recommend for Air Mass Meter cars as technically the system does not know where the excess air has suddenly disappeared to, which can effect performance. However, the noise outweighs the technical compromise and this type of valve is associated with your typical "boy racer".

Re-Cir Dump Valve = Used for car equipped with MAF or without MAF. Dumps the excess boost on overun to the compressor inlet after the MAF ensuring that the ECU retains the correct mass calculation. These are typically silent as the noise is damped by the filtration system.

Any surge/choke can prematurely damage the turbo but its not related to what valve you decide to use, if any.