I know what it sounds like, vivs smart does it very loudly and wrc cars make a lovely chatter too.

I don't fully understand what causes it though. I did think it was the noise resulting from a stalled turbo, audible through the open wastegate. But that doesn't make any sense. WRC cars don't let the turbo stall, and the smart has a DV to prevent it.

So where does the noise come from, is it because the valve is pulsed open/shut quickly? Someone suggested that, but it doesn't sound right.. surely it just opens at X boost pressure.

It became more noticeable on the smart when the airbox lid was removed. Why does the sound come from the airbox?! That kinda supported my stalled turbin/compressor theory. But i'll confess, i don't really know.

I've asked this on the smart forums, but most of them think checking their tyre pressure is hardcore mechanic work - so don't really know anything.

You get also that sound if you don't have a blowoff/dumpvalve.
This is the sound of the air that goes back into your airfilter right through the turbine and is bad.

The wastegate sound....I also want to know how you can get it.

I think it's cause they have an external wastgate.

http://web.bitnet.net/liqqe/MADs Nissan 200SX s14a.wmv
You mean that sound..The woosh, woosh whoost after Throttle release.
(it's not a butterfly Blowoff I think, so it must be the wastegate)

That sound cooler than a HKS SSQV BOV

dont you have to have an external wastegate?

The wrc cars do it because of a system put onto the engine/turbo which is there to reduce lag and STOP turbo stall.
Dont know how though.

afaik

TurboCinqy said:

I think it's cause they have an external wastgate.

http://web.bitnet.net/liqqe/MADs Nissan 200SX s14a.wmv
You mean that sound..The woosh, woosh whoost after Throttle release.
(it's not a butterfly Blowoff I think, so it must be the wastegate)

That sound cooler than a HKS SSQV BOV

Click to expand...

new tires pls

WRC anti lag works by retarding the timing, causing unburnt fuel to enter the turbo. it detonates on the blades and keeps it moving. Thats what the loud bangs on overrun are. That system doesn't cause the chatter though does it?

http://tackycheese.net/images/cars/smart/bypass/progress_way.avi

You can hear the wastegate in that clip, thats in vivs smart.

HKS sequential dv's make a lovely sound

Jay - no, you don't need an external wastegate. the smart has it in the turbine housing, which is part of the exhaust manifold

ah i see i get ya

go for the firework sound like this animal :yum:

http://videos.streetfire.net/Player.aspx?fileid=BBFC6129-9FFA-4CD0-AA03-B78692BC844C&kw=11&p=0

thats awesome

some rather tastey vids on there aswell, i often go through them all

i keep telling alex that wastegate flutter is how a turbo should sound but nooo he doesnt agree

well it depends why it does the noise.. if its the blades stalling then it might sound good but its not a good thing

true true, i dont think it would be though, just look at the way cossie`s and supra`s go and they flutter :yum:

i always assumed the chatter was the air pressure equalising past the wastgate 'door'. with the door flapping as air rushed past?

could be wrong though

arc said:

well it depends why it does the noise.. if its the blades stalling then it might sound good but its not a good thing

Click to expand...

Not clever at all...the stall causes massive amounts of bearing wear Id think....thats why WRC cars eat turbo's

no, wrc eat turbos because they have fuel exploding on the blades. they dont stall them!

a wastegate shouldn't flap, its pressure actuatated - it should slam open to closed with boost pressure.

the wastegate is exhaust side, so its going to be exhaust gasses rushing through - which makes no sense to the noise getting louder with the airbox lid off.

arc said:

no, wrc eat turbos because they have fuel exploding on the blades. they dont stall them!

Click to expand...

I see. Learn something new every day eh?

The chattering sound is the Blowoff valve letting the pressure out when throttle is closed down.
You need to let out the pressure on the compressor site of turbo to prevent turbo in stalling when you shift the gears.
Normally an open blowoff valve gives a small "tifff" sound right after throttle is taken down, but when you have a really high turbo pressure the open blowoff valve can chatter a little when it's letting out pressure.
Not all blowoff valves makes a chattering sound.

You cannot hear a wastegate opening up...
The wastegate sit on the turbine side (exhaust) of the turbo.

anti lag explained.

https://www.fiatforum.com/showpost.php?p=523158&postcount=26

i aint talking about anti lag, and i'm not talking about dumpvalves.

the video i posted, the noise that the car makes is not a blow off / dump valve. It has one fitted, but it doesn't sound like that. It makes the same noise when the dv/bfv is removed. and the car doesnt have as stock.

as we know, WRC don't have dump valves and they chatter. It's called wastegate chatter. Maybe i'm not being specific enough in what i'm asking.

so, does anyone know what casues wastegate chatter.. and no body tell me its the dumpvalve...

Chatter is the compressed air rushing back through the turbo the wrong way when the throttle is lifted.

A Jap mag called J-tuned did a few pages on it a few months ago, it’s basically the sound slowing the blades down in the housing.

I dont have a scanner but try a search on J-turner and see if you can find anything.

I ran a tuned subaru for a while and it had chatter while it was very Ill, just before it ate a turbo and sucked the blades into the engine the waste gate spring had given up so it was running more and more boost until it couldn’t take any more .