Joe is doing a fairly good job of convincing me to put a dump valve back on my car. I run without one for the past 5-6 years and 40k with no bother and have the flutter sound which, frankly, I love.

Does anyone have any footage of the noise a Forge or other recirc makes?

I'm absolutely not going for a blow off valve, like the DV26, I had one of those and hated it.

No replies, I wonder why Chris

Time has come to order that Forge 008 and a catch tank for the breather

I don't really notice it! or i have got used to it

Its only really noticeable if you have a heavy right foot when driving slowly if that makes sense!

I always wondered why the astras vxr's and RS focus made so much noise and i think thats how they do it?

I am in the market for a different air filter but as per everything else just don't ever seem to find the time at the moment!

I have a forge recirc DV. I will PM you how it sounds with gt2871 and gt28rs as it does sound different.

One thing to remember - on boost, when you close the throttle body, no Dv causes the compressed air find its way to escape by hitting the compressor wheel on its exit side, causing unwanted turbo stall. That's what you get that sexy flutter. But still, you don't really want it. Atmospheric dv helps air to escape, thus, helps preventing turbo stall. Now, a recirc dv is even better, as it wents the excess of air to the intake pipe, helping the compressor wheel spin. If you'll have the entry point at an angle, and close to the compressor wheel you can see the benefits. This is how I have it set up. I also tested an atmospheric dv and the turbo response suffered, the car became jerky between gear shifts, the afr went off. So, my recommendation - go for a recirc dv.

Cheers for the input guys and links in the PM. The gear change is definitely jerky with no DV on at all.

Can you explain in more detail what you mean by entry point at an angle?

Sure. With the recirc DV you have air return pipe that goes from the DV to turbo induction pipe. So, let's say you are making a SIP for yourself, you can then have that pipe connected at an angle close to the turbo's cold side so that it blows the excess of compressed air at the compressor wheel to help it spin / prevent stall. Does it make sense?

Got you, cheers

I ran without one on my RX7 for a good while - journal bearing turbo, so arguably OK.

Flutter was silly loud on mid throttle lift and throttle response when 'feathering' with no DV was poor. Definitely improved when I put a proper atmospheric DV back on.

Aaaaaaah! Just get a blow off valve, not only does it sound cool to 'say' but it makes a great noise that impresses everyone. It's the international sound of 'fast' don't you know!!

Get a double trumpet one, post some vids scaring the locals, job done!

I once had a HKS jobby that sounded like a pigeon farting / duck getting squashed. I truly loved that one!

You mean it sounded like this?