Technical Wastegate chatter

[arc]

so i was right in what i was thinking, and it doesn't really have anything to do with the wastegate really.

what i dont get though, it shouldnt be rushing back the wrong way on the likes of WRC cars - surely? If the ALS can keep the turbo spinning enough to generate a decent pressure in the inelt manifold, surely that means the turbo isnt slowing much if at all.

 

[Curtis]

blow into a desk fan it wont slow down but the blades will make a noise from the air trying to slow it down .

same sort of thing , anti lag is making it spin and the blow back is trying to make it stop.
if you didnt have the anti lag the turbo would stall

the wastegate just blows off thye XS pressure and a pre set level , if there were no pre set level it would just blow up (like my car did)

 

[arc]

ah, something in my brain just clicked.

being picky though, wastegate doesnt blow off excess pressure, it just diverts exhaust around the turbine once a preset level of boost on the inlet side is reached.

 

[Curtis]

true , depends on the set up etc

remote wastegates and blow out the air or redivert it

please to have helped

 

[arc]

wouldnt that be a dumpvalve / blow off valve if it was dumping air / inlet pressure though?

 

[CINQYBOY]

If you want a really loud chatter i surgest you fit a cossie group A K&N
. the sound is awesome .Also when the turbo is spinning up is sounds like it will suck up everything in its way.Dump valves have been around for about 12yrs now and people still choose a tishhh over abit of pigeon chatter.

 

[beastyjay]

you can get custom cossies filter for a corsa, they`re fooking massive and no way in hell would fit in the cinq bay lol

 

[Curtis]

wouldnt that be a dumpvalve / blow off valve if it was dumping air / inlet pressure though?

the wastegate will either divert into the atmosphere on into the exhaust , the turbo slows down , the boost pressure drops and the wastegate closes again .
EG a gear change

 

[TurboCinqy1250]

I'm using a BOV but when I release the throttle i'll still here a Woosh.
After a long time thinking what it could be. I think it's still the sound of the turbo in the Airfilter. You can hear it about 100 meters away with the front in the right direction.

If it's not the wastegate then it must be aa butterfly Blow Off. With high pressure boost setup's.

Next week i'm going on a Dyno to get the ignition and AFR right. I'll make a video of it and put it online.

 

[arc]

you're still going to hear a whoosh with a BOV.. of course, its dumping atmopshere.

how much boost u run, that smart runs just under 2bar. thats failrly high boost!

 

[TurboCinqy1250]

you're still going to hear a whoosh with a BOV.. of course, its dumping atmopshere.

how much boost u run, that smart runs just under 2bar. thats failrly high boost!

The woosh isn't a BOV woosh. It a woosh sound from my left wheel. In first instanse I was thinking my wheel hits the fender. But the airfilter is right behind my bumper on the left site (just before the wheel)

And I'm running at 1 bar.

Don't have a driving movie yet. Only without exhaust
http://members.lycos.nl/turbocinqy/forums/Fiatforum-filmpje.WMV

 

[SteveNZ]

The noise that you guys refer to as wastegate chatter has nothing to do with the wastegate. And I doubt there is any such thing as a chattering wastegate either. Any noise assioated with the wastegate needs to exit via the exhaust, you are not going to hear it. Ive heard a lot of wastegates with external venting unmuffled pipes and they just sould like a huge roar.

The noise is nothing mroe than compressor surge. This is cause by operating the compressor in an area it cannot work at. i.e. high boost, low airflow. It is very bad for the turbo. WRC cars make the noise as they have antilag. This causes the compressor to surge as its making full boost at idle! This is also why they dont have a BOV as there is never any vacuum in the manifold to operate it.

 

[RS Pilot]

If Viv's Smart makes the chattering noise when it has a dump valve fitted then the dump valve has been plumbed up incorrectly. As already explained within the thread, the chattering noise is the turbo stalling. Installation of a dump valve stops the turbo stalling. Make sure the small 'actuator' pipe to the dump valve is plumbed to the correct side of the throttle butterfly, otherwise it's doing nothing.

 

[arc]

This is why i didn't get what was going on, i've always known this noise as wastegate chatter - i'm not sure why, but fail to see what it has to do with the wastegate.

What was said about the compressed air flowing back, but not stalling the turbo made sense till i thought about it. I was thinking, close throttle, air hits closed butterfly and bounces backward, manifold pressured spikes, bov opens and vents the charge.

Theres no time on a road car when the compressor is spinning, and the charge is forced backwards through the turbo. I can understand on rally car, but i'm on about road cars.

Make sure the small 'actuator' pipe to the dump valve is plumbed to the correct side of the throttle butterfly, otherwise it's doing nothing

That would be anything line on the inlet manifold then, yeah? It currently runs off the same line that runs the boost gauge and the exhaust bypass actuator.

The DV dumps when the throttle is lifted, so i can only assume it does work properly.

What was the noise that RX7 was making that jay posted up. That didn't seem like the kinda car where they would forget to prevent turbo stall, and by the sounds of things it wasn't stalling as it'd take a turbo that size 20mins to spool up again!

 

[Curtis]

see if you can get a copy of the aug 2005 j-tuner , if I cant find my old copy I will post it to you for a read

the explain everything over 4 pages and wastegate chatter is totally made up , the noise has nothing at all to do with the wastegate .

 

[RS Pilot]

The pipe for the wastegate is usually between the turbos compressor and the throttle butterfly (if not taken directly from the turbos compressor housing). You need the dump valve pipe to be taken after the throttle butterfly.

 

[beastyjay]

http://www.geocities.com/drivetoish/rst_0-60.mpg oooooh yeah

 

[mase]

http://www.geocities.com/drivetoish/rst_0-60.mpg oooooh yeah

fookin awesome cars..... :worship: especially the series 1's

 

[beastyjay]

dont you just know it