I have the traditional psshhtt noise at the min but have always loved the ones found on cossie's

like the sound of the one in this link YouTube - Cosworth on the mountain

can you get them for impreza's?

Tom

 

i like the sneezing noise.. i have a forge dumpvalve and the wife always comments the car on the sneezing!!

 

i guess the sneezing noise is the traditional bov?

 

get a better idea of the one i want in this clip

YouTube - Cosworth on the mountain

 

Sounds like a front mounted intercooler to me

 

Isn't that actuator chatter

 

so does anyone know where i can get one??

 

That sound actually comes from not having a dump valve or having the spring set so tight that it doesn't open at all.

You can block off your DV like I did to get the sound. You can do it with the TD series turbo, it's not so safe with the VF turbos, there's a chance of them getting damaged by the air surges in the compressor.

 

To get the noise your after you need to remove your dumpvale and block up all the connecting pipes. Then fit an induction kit and you will hear it.

Its the noise made when the air forces its way back through the comp wheel of the turbo

Try doing a search mate this has been done to death on every turbo'd car forum

 

Yep, that's the noise, turbo stall. Sounds good doesn't it!!

Clarkson described it as making the car sound like a squirrel mincer!

Depending on what turbo you have, not always a good idea to blank off the DV though.

ns04

 

Piston dump valves make different noises too. Compared to the older diaphram? ones.

I had a baileys piston one on my GTi-R. Sounded much different to the Lancia's. Higher pitched.

Then i grew up

(flame suit on and zipped up)







Do fancy blocking the DV and hearing that though.

 

so whats the worst that can happen, if you blank off the dv

 

YouTube - BOV comparison

this is a good vid for you mate hth

 

Dead turbo, I believe. Depends on the model of turbo and, of course, its condition.

*Awaits experts opinion*

Ns04

 

The connector pipe came off my Forge dumpvalve the other day, I thought the "chatter / flutter" noise sounded great!

I have a VF35 turbo and have been told its not good to run without the dumpvalve, but I would love to somehow just have very loud chatter noise!

Will my turbo really die if I run with no dumpvalve? (also awaits experts opinions)

What I liked is I could pull away fairly slowly not giving it too much and it would make the fluttering noise at very low revs, my Forge dumpvalve seems to only come alive after 3500 rpm!

 

surely compressed air going the wrong way through a turbo/compressor i snever good though i admit the noise does sound good. thyats the noise you hear on the wrc cars but then again they do get stripped and re built a little more frequently than yours or mine lol. i have just fitted a HKS SSQV bov and i love it though may find it will get annoying after a while. At low boost/pressure its wheezing like my dog whens he's bores but the higher the revs the more of a chirp you get then to a dmmmppst (the way i'd try phonetically spell it lol)

work with a guy that destroyed the turbo in his legacy blocking off both pipes. sounded good but you kinda knew it wasnt right. dashboard was like blackpool too with the CEL lights etc

 

What a load of Bollox AGAIN.....

The noise is compressor surge, or compressor stall, its when the compressor is running at a high pressure ratio (boost) at lowish airflows (therefore above the surge line on the compressor map) and the blades 'stall' (like an aircraft wing) and the flow seperates off the back face of each blade, the pressure ratio at that point drops and the flow reattaches, pressure ratio incraeses again back into surge. There is no back flow thorugh the compressor (urban myth/legend or bollox at your preferance), nor is it 'wastegate' or 'actuator' chatter.

The MHI TD series turbo's are wuite robust and less likely to be damaged during surge, the IHI VF's are less robust, either way its not good for turbo longevity, especially on smaller turbo cars when you can get surge much more often.

Simon

 

Hi there,

I've asked a couple of experts about this, as I'm getting an FMIC and -as a result- an induction kit soon and wondered about the dump valve issue. I've been advised by both David at APi and Bob Rawle that the VF35 will be ok without a dump valve. I'll give it a go and see what happens

Ns04

 

YouTube - Christmas Song....Bottom Burping


well its s kind of dump valve lol

have a look at Scooby Clinic | The UK's Largest Independent Subaru Specialists | 01246 590 807 - Chesterfield S42 6QX, sure they've got the GFB dump valve noises on there

 

PMSL at one of the comments regarding that video! Youtube really is an endless source of wonder when it comes to probing the depths of internet trolling!

vandeman10 (6 days ago)



You sicken me! Dirty piece of SH*T!

 

The last DV noise made me

 

o heres another option as well

YouTube - blow off valve duck call


o also i can confirm they do work with scoobs

YouTube - Duck BOV on a wrx hilarious

 

So this is how they test em!!

YouTube - Condom on Blow Off Valve

 

pmsl, very stretchy arnt they,,, lol

 

Oh! Man!

 

not totally true, you can get reverse flow in deep stall,

From 'Surge avoidance for compressor systems, Robert C white and Rainer Kurz'

'When a compressor approaches its surge limit, some of its components (diffusers,impellers) may start to operate in stall. Stall occurs when the gas flow starts to separate from a flow surface........Stall in turbomachines often appears as rotating stall, when localised regions of separated flow move alon the diffuser at speeds below the rotational speed......Flow will decrease and subsequently the head capability of the compressor will also decrease, As the head capabiity decreases, the flow decreases. Once the compressor can no longer meet the external head, FLOW REVERSES.'

Lots of technical articles on the web about surge in compressor systems, though most are aimed at gas turbines with axial compressors, though the principles are the same.

Thing also to remember is that a dump valve is fitted to protect the turbo, however it actually results in the turbo slowing down slightly faster as energy stored as momentum is lost by moving a mass of air through the dump route.

 

Ideal, let me know how you get on as I would love to have the loud fluttering noise as long as it wasnt damaging anything.

 

Gary,
While in theory it can back flow, no-one (and I mean pro's like Cosworth etc) have ever measured this on a car engine as there is always sufficient flow through the throttle to stop it - valid point though.

Simon

 

The only decent noise that youll get from a VTA air bypass valve, is after fitting it to a quality duck call.

Vrooooom.....QUACK !
Vrooooom.....QUACK !

 

Fair enough,

My experience is only with 10MW gas circulators and rotating stall.